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1.
Planta Med ; 90(4): 286-297, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38286405

RESUMO

Extracellular senile plaques and intraneuronal neurofibrillary tangles are two devastating brain proteinopathies that are indicative of Alzheimer's disease, the most prevalent type of dementia. Currently, no effective medications are available to stop or reverse Alzheimer's disease. Ginkgo biloba extract, commonly referred to as EGb 761, is a natural product made from the leaves of the G. biloba tree. It has long been demonstrated to have therapeutic benefits in Alzheimer's disease. The current study assessed the beneficial effects of EGb 761 against Alzheimer's disease in comparison with memantine, a standard treatment for Alzheimer's disease. The scopolamine-heavy metals mixture rat Alzheimer's disease model is a newly created model to study the effects of EGb 761 oral therapy on cognitive performance and other Alzheimer's disease-like changes over a 28-day experimental period. This new Alzheimer's disease model provides better criteria for Alzheimer's disease hallmarks than the conventional scopolamine model. The EGb 761 reversed memory and learning deficits induced by the scopolamine-heavy metals mixture. These outcomes were linked to a more pronounced inhibitory effect on acetylcholinesterase, caspase-3, hippocampal amyloid-beta protein (Aß1 - 42), phosphorylated tau protein counts, and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1ß) compared to the memantine-treated group. Furthermore, EGb 761 treatment considerably reduced lipid peroxidation (malondialdehyde) and improved reduced glutathione levels compared to memantine. Our results suggest EGb 761's potential in treating central nervous system disorders. It's a promising candidate for future Alzheimer's disease therapeutic exploration. This study also highlights the need for future research to focus on the positive benefits of herbal medicines.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Extrato de Ginkgo , Metais Pesados , Animais , Ratos , Doença de Alzheimer/tratamento farmacológico , Memantina/farmacologia , Memantina/uso terapêutico , Ginkgo biloba , Acetilcolinesterase/uso terapêutico , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Disfunção Cognitiva/tratamento farmacológico , Metais Pesados/uso terapêutico , Derivados da Escopolamina/uso terapêutico
2.
BMC Plant Biol ; 23(1): 655, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38110871

RESUMO

BACKGROUND: Although it is well recognized that core root microorganisms contribute to plant health and productivity, little is known about their role to the accumulation of secondary metabolites. The roots of Anisodus tanguticus, a traditional herbal medication utilized by Tibetan medicine, are rich in tropane alkaloids. We collected wild A. tanguticus populations throughout a 1500 km transect on the Qinghai-Tibetan Plateau. RESULTS: Our results showed that despite sampling at a distance of 1500 km, the root of A. tanguticus selectively recruits core root bacteria. We obtained 102 root bacterial core OTUs, and although their number only accounted for 2.99% of the total, their relative abundance accounted for 73% of the total. Spearman correlation and random forest analyses revealed that the composition of core root microbiomes was related to anisodine contents, aboveground biomass and nitrogen contents of Anisodus tanguticus. Among them, the main role is played by Rhizobacter, Variovorax, Polaromonas, and Mycobacterium genus that are significantly enriched in roots. Functional prediction by FAPROTAX showed that nitrogen-cycling microorganisms and pathogenic bacteria are strongly associated with anisodine contents, aboveground biomass and nitrogen contents of Anisodus tanguticus. CONCLUSIONS: Our findings show that the root selectively recruits core root bacteria and revealed that the core microbiomes and microbial functions potentially contributed to the anisodine contents, aboveground biomass and nitrogen contents of the plant. This work may increase our understanding of the interactions between microorganisms and plants and improve our ability to manage root microbiota to promote sustainable production of herbal medicines.


Assuntos
Derivados da Escopolamina , Tropanos , Derivados da Escopolamina/metabolismo , Tropanos/metabolismo , Bactérias , Nitrogênio/metabolismo , Raízes de Plantas/metabolismo
3.
Bioorg Chem ; 131: 106308, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36516520

RESUMO

Muscarine acetylcholine receptors (mAChRs) regulate a variety of central and peripheral physiological functions and emerge as important therapeutic targets for a number of diseases including chronic obstructive pulmonary disease (COPD). Inspired by two active natural products, we designed and synthesized a series of 2-(2,2-diarylethyl)-cyclamine derivatives for screening M3 mAChR antagonists. On this skeleton, the structural units including N heterocycle, aryl groups and its substituents on aryl were examined and resulted in a clear structure-activity relationships on the M3 mAChR. In general, these 2-(2,2-diarylethyl)-cyclamine derivatives exhibited good to excellent M3 antagonistic potency and receptor selectivity. The most active 5b-C1 had an IC50 value of 3 nM and the most of compound 6 displayed inactivity against histamine H1 receptor closely related to M3. In in vitro and in vivo evaluations of tracheo-relaxation function, some compounds even showed comparable activity to tiotropium bromide, a known blockbuster drug for COPD. Such excellent properties made these novel compounds potential candidates for COPD drug development.


Assuntos
Antagonistas Muscarínicos , Doença Pulmonar Obstrutiva Crônica , Humanos , Antagonistas Muscarínicos/uso terapêutico , Derivados da Escopolamina/química , Derivados da Escopolamina/uso terapêutico , Receptor Muscarínico M3 , Brometo de Tiotrópio/uso terapêutico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico
4.
Int Urogynecol J ; 34(8): 1689-1696, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36719449

RESUMO

INTRODUCTION AND HYPOTHESIS: Both urogynecologic surgeries and transdermal scopolamine (TDS) patches are independently associated with postoperative urinary retention (POUR). It is unclear if the risk of POUR increases when these interventions are used in combination. This systematic review and meta-analysis aim to synthesize current evidence to optimize clinical management and outcomes for patients undergoing urogynecologic procedures. METHODS: This systematic review was conducted in concordance with the PRISMA 2020 guidelines. MEDLINE, ClinicalTrials.gov, and Cochrane Library were searched. Publications were filtered by inclusion and exclusion criteria. Inclusion criteria required: (1) preoperative or perioperative application of TDS, (2) surgery indicated for stress urinary incontinence and/or pelvic organ prolapse, (3) results given for postoperative voiding trials, and (4) were available in English. Exclusion criteria included: (1) oral or parenteral formulations of scopolamine, (2) administration of alternative preoperative antiemetics, and (3) use of combination antiemetic therapy. Quality was assessed using the Joanna Briggs Institute Checklist. Publication bias was evaluated via the ROBINS-I assessment tool, and Egger regression and Begg and Mazumumdar rank correlation tests. A meta-analysis was conducted using Meta-Essentials Excel Workbook. RESULTS: Four publications were identified which complied with inclusion and exclusion criteria. Included studies comprised 752 patients (237 experimental group, 515 control group). All were retrospective cohort studies conducted via chart review in America. Meta-analysis revealed a risk ratio (RR) of 2.35 with a confidence interval (CI) of 0.61 to 9.07, indicating a positive association between TDS and POUR, but without statistical significance. CONCLUSIONS: Current evidence suggests that TDS application may be associated with increased risk of POUR following urogynecologic procedures. While research on this topic is greatly limited, this systematic review and meta-analysis highlights that alternative antiemetic therapy may be necessary for patients undergoing such interventions in effort to limit the risk of POUR.


Assuntos
Antieméticos , Prolapso de Órgão Pélvico , Retenção Urinária , Humanos , Retenção Urinária/induzido quimicamente , Antieméticos/uso terapêutico , Estudos Retrospectivos , Prolapso de Órgão Pélvico/cirurgia , Complicações Pós-Operatórias/etiologia , Derivados da Escopolamina
5.
Lung ; 201(1): 9-15, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36746813

RESUMO

PURPOSE: There are limited studies on the use of bronchodilators for the treatment of bronchiectasis. This study investigated the efficacy of tiotropium in patients with bronchiectasis and airflow limitation. METHODS: This study was a prospective cohort study, including 169 patients with bronchiectasis and airflow limitation from 2015 to 2019. The clinical outcomes observed in our study were the effect of tiotropium on the frequency of moderate exacerbations, the time to the first severe exacerbation, and the annual decline in FEV1. RESULTS: After 12 months, the annual decline in the FEV1 after bronchodilator use was 27.08 ml or 42.9 ml per year in the group with or without tiotropium, respectively. Treatment with tiotropium was associated with a decreased risk of moderate exacerbation of bronchiectasis (Adjusted RR 0.618 95% CI 0.493-0.774; P < 0.005). The time to the first severe acute exacerbation of bronchiectasis in the tiotropium group was longer than the non-tiotropium group (Adjusted HR 0.333 95% CI 0.219-0.506; P < 0.001). CONCLUSION: In conclusion, prospective cohort study showed that tiotropium effectively ameliorated the annual decline in the FEV1, with a lower-risk rate of moderate exacerbations and prolonging the time to the first-time severe exacerbation in patients with bronchiectasis and airflow limitation.


Assuntos
Bronquiectasia , Doença Pulmonar Obstrutiva Crônica , Humanos , Brometo de Tiotrópio/uso terapêutico , Estudos Prospectivos , Derivados da Escopolamina/uso terapêutico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Broncodilatadores/uso terapêutico , Resultado do Tratamento
6.
Allergol Immunopathol (Madr) ; 51(4): 131-138, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37422789

RESUMO

OBJECTIVE: To investigate the clinical efficacy of combining budesonide formoterol with tiotropium bromide for treating asthma-chronic obstructive pulmonary disease overlap syndrome (AOCS). METHODS: The data of 104 patients with AOCS admitted to our hospital from December 2019 to December 2020 were assessed, randomly and divided into an experimental group (comprising 52 patients, receiving drug combination therapy) and a conventional group (comprising 52 patients, receiving drug therapy alone). Patients' clinical efficacy, pulmonary function, fractioned exhaled nitric oxide (FeNO), immune function, endothelial function, serum lipid peroxidation injury indexes, adverse reactions, and quality of life scores were compared. RESULTS: Prior to treatment, no significant differences were observed in various pulmonary function indicators, FeNO, immune function, endothelial function, and lipid peroxidation injury indexes between the two groups (P > 0.05). However, after treatment, all observation indexes in both groups improved to different levels, with the experimental group -demonstrating -significantly superior improvement, compared to the conventional group (P < 0.05). We also observed that adverse reactions in the experimental group were significantly lower than in the conventional group (P < 0.05). CONCLUSION: The combination of budesonide formoterol to tiotropium bromide in treating asthma-COPD overlap syndrome may significantly improve pulmonary function, endothelial function, and immune status of patients and encourage the recovery of serum lipid peroxidation injury; therefore, this may deserve widespread adoption and application.


Assuntos
Síndrome de Sobreposição da Doença Pulmonar Obstrutiva Crônica e Asma , Doença Pulmonar Obstrutiva Crônica , Humanos , Brometo de Tiotrópio/uso terapêutico , Broncodilatadores/uso terapêutico , Síndrome de Sobreposição da Doença Pulmonar Obstrutiva Crônica e Asma/tratamento farmacológico , Qualidade de Vida , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Derivados da Escopolamina/efeitos adversos , Combinação Budesonida e Fumarato de Formoterol/uso terapêutico , Budesonida/uso terapêutico
7.
Chem Biodivers ; 20(11): e202300776, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37811911

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disease that occurs especially in advanced ages. It reduces the quality of life of both the patient and their relatives. In addition to its primary effects, AD causes metabolic defects and tissues are damaged due to these effects. Oxidative stress damages cells by disrupting antioxidant/oxidant balance in many tissues, especially due to AD. In individuals with AD and the elderly, lens tissue is damaged due to oxidative stress and may cause vision loss. Therefore, it is very important to investigate herbal products that both prevent/cure AD and reduce AD-related oxidative stress, as they may have fewer side effects. In this study, the protective effects of parsley (Petroselinum crispum) extract on lens tissues of an experimental AD model induced by scopolamine were examined and evaluated through biochemical parameters. The result of biochemical experiments and principal component analysis, was observed that parsley extract had a therapeutic effect by reducing oxidative stress in lens tissues of experimentally induced AD rats. It can be suggested that the phenolic and flavonoid-rich content of parsley extract may have caused the reduction of oxidative damage in lens tissues and can be used to protect lens tissue against oxidative stress due to AD disease.


Assuntos
Doenças Neurodegenerativas , Petroselinum , Humanos , Ratos , Animais , Idoso , Petroselinum/química , Extratos Vegetais/metabolismo , Doenças Neurodegenerativas/tratamento farmacológico , Qualidade de Vida , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Estresse Oxidativo , Derivados da Escopolamina/metabolismo , Derivados da Escopolamina/farmacologia
8.
Int J Mol Sci ; 24(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37108332

RESUMO

Despite its increasing application in pursing potential ligands, the capacity of receptor affinity chromatography is greatly challenged as most current research studies lack a comprehensive characterization of the ligand-receptor interaction, particularly when simultaneously determining their binding thermodynamics and kinetics. This work developed an immobilized M3 muscarinic receptor (M3R) affinity column by fixing M3R on amino polystyrene microspheres via the interaction of a 6-chlorohexanoic acid linker with haloalkane dehalogenase. The efficiency of the immobilized M3R was tested by characterizing the binding thermodynamics and kinetics of three known drugs to immobilized M3R using a frontal analysis and the peak profiling method, as well as by analyzing the bioactive compounds in Daturae Flos (DF) extract. The data showed that the immobilized M3R demonstrated good specificity, stability, and competence for analyzing drug-protein interactions. The association constants of (-)-scopolamine hydrochloride, atropine sulfate, and pilocarpine to M3R were determined to be (2.39 ± 0.03) × 104, (3.71 ± 0.03) × 104, and (2.73 ± 0.04) × 104 M-1, respectively, with dissociation rate constants of 27.47 ± 0.65, 14.28 ± 0.17, and 10.70 ± 0.35 min-1, respectively. Hyoscyamine and scopolamine were verified as the bioactive compounds that bind to M3R in the DF extract. Our results suggest that the immobilized M3R method was capable of determining drug-protein binding parameters and probing specific ligands in a natural plant, thus enhancing the effectiveness of receptor affinity chromatography in diverse stages of drug discovery.


Assuntos
Pilocarpina , Receptor Muscarínico M3 , Receptor Muscarínico M3/metabolismo , Derivados da Escopolamina , Extratos Vegetais/farmacologia
9.
Pak J Pharm Sci ; 36(6): 1743-1747, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38124414

RESUMO

An accurate and reliable HPLC-MS/MS method has been established for the simultaneous determination of seven toxic components in the Chinese medicine ShenFuTuoDu capsules. The seven toxic components were separated on a Shimadzu Shim-pack GIST C18 column (3.0 mm×50 mm, 3.0 µm) with methanol and water (containing 0.1% formic acid) as the mobile phase by gradient elution. The flow rate was 0.5 mL•min-1. The column temperature was 25°C and the injection volume was 5µL. An ESI+ scan combined with MRM was adopted and the instrument parameters were as follows: ion source voltage, 5.5 kV; ion source temperature, 600oC; curtain gas, 68.95 kPa; atomized gas, 344.75 kPa; auxiliary gas, 344.75 kPa. The linear relationships of the seven components were good (R2>0.9937). The average recoveries were 95.2%-106.7% with RSD of 0.79%-5.27% (n=6). The seven toxic components of scopolamine, atropine, rhynchophylline, isorhynchophylline, benzoylaconine, benzoylmesaconine and benzoylhypaconine in six batches of ShenFuTuoDu capsules were 5.99-18.48µg•g-1, 6.36-14.79µg•g-1, 3.71-15.45µg•g-1, 7.90-15.08µg•g-1, 19.05-44.58µg•g-1, 117.38-248.26µg•g-1 and 19.74-79.49µg•g-1, respectively. Precision, stability and repeatability test RSDs were less than 7.17% (n=6). The method is suitable for the simultaneous determination of scopolamine, atropine, rhynchophylline, isorhynchophylline, benzoylaconine, benzoylmesaconine and benzoylhypaconine. It can be used for the quality control of ShenFuTuoDu capsules.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas em Tandem , Espectrometria de Massa com Cromatografia Líquida , Cromatografia Líquida de Alta Pressão , Cápsulas , Derivados da Escopolamina , Derivados da Atropina
10.
Neurobiol Dis ; 171: 105797, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35738477

RESUMO

BACKGROUND/OBJECTIVE: Deep brain stimulation (DBS) of the nucleus basalis of Meynert (NBM) has gained interest as a potential therapy for treatment-resistant dementia. However, optimal stimulation parameters and mechanisms of action are yet to be elucidated. METHODS: First, we assessed NBM DBS at different stimulation parameters in a scopolamine-induced rat model of dementia. Rats were tested in the object location task with the following conditions: (i) low and high frequency (20 Hz or 120 Hz), (ii) monophasic or biphasic pulse shape (iii) continuous or intermittent DBS (20s on, 40s off) and 100 µA amplitude. Thereafter, rats were stimulated with the most effective parameter followed by 5-bromo-2'-deoxyuridine (BrdU) administration and perfused 4 weeks later. We then evaluated the effects of NBM DBS on hippocampal neurogenesis, synaptic plasticity, and on cholinergic fibres in the perirhinal and cingulate cortex using immunohistochemistry. We also performed in-vivo microdialysis to assess circuit-wide effects of NBM DBS on hippocampal acetylcholine levels during on and off stimulation. RESULTS: Biphasic, low frequency and intermittent NBM DBS reversed the memory impairing effects of scopolamine when compared to sham rats. We found that acute stimulation promoted proliferation in the dentate gyrus, increased synaptic plasticity in the CA1 and CA3 subregion of the hippocampus, and increased length of cholinergic fibres in the cingulate gyrus. There was no difference regarding hippocampal acetylcholine levels between the groups. CONCLUSION: These findings suggest that the potential mechanism of action of the induced memory enhancement through NBM DBS might be due to selective neuroplastic and neurochemical changes.


Assuntos
Estimulação Encefálica Profunda , Demência , Acetilcolina , Animais , Núcleo Basal de Meynert , Demência/terapia , Ratos , Derivados da Escopolamina
11.
Eur Respir J ; 59(6)2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34795034

RESUMO

BACKGROUND: Tiotropium via the HandiHaler device is an established long-acting, anticholinergic bronchodilator that prevents exacerbations and improves lung function in patients with chronic obstructive pulmonary disease. We hypothesised that tiotropium would reduce pulmonary exacerbations and improve lung function in patients with stable bronchiectasis and airflow limitation, and assessed the effect of tiotropium on these outcomes. METHODS: In a randomised, double-blind, two-period crossover trial, we recruited adult patients from three hospitals in New Zealand. Patients were excluded if they had a smoking history of >20 pack-years. Patients were assigned to either the tiotropium-placebo or placebo-tiotropium sequence in a 1:1 ratio, using randomly permuted blocks stratified by centre. Participants and investigators were masked to treatment allocation. Eligible patients received tiotropium 18 µg via HandiHaler daily for 6 months followed by 6 months of placebo, or vice versa, with a washout period of 4 weeks. The primary end-point was rate of event-based exacerbations during the 6-month period. Primary analyses were carried out in an intention-to-treat set. RESULTS: 90 patients were randomly assigned and 85 completed both treatment cycles. The rate of exacerbations was 2.17 per year under the tiotropium treatment and 2.27 per year under placebo (rate ratio 0.96, 95% CI 0.72-1.27; p=0.77). Tiotropium, compared with placebo, improved forced expiratory volume in 1 s by 58 mL (95% CI 23-92 mL; p=0.002). Adverse events were similar under both treatments. CONCLUSIONS: Tiotropium via HandiHaler over 6 months significantly improved lung function but not frequency of exacerbations. Further research is required to understand the clinical context and significance of these findings.


Assuntos
Bronquiectasia , Doença Pulmonar Obstrutiva Crônica , Adulto , Bronquiectasia/tratamento farmacológico , Broncodilatadores , Estudos Cross-Over , Método Duplo-Cego , Volume Expiratório Forçado , Humanos , Doença Pulmonar Obstrutiva Crônica/induzido quimicamente , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Derivados da Escopolamina/efeitos adversos , Brometo de Tiotrópio/uso terapêutico , Resultado do Tratamento
12.
Int J Neuropsychopharmacol ; 25(6): 498-511, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35152284

RESUMO

BACKGROUND: Short chain fatty acids (SCFA), such as butyric acid (BA), derived from the intestinal fermentation of dietary fiber and contained in dairy products, are gaining interest in relation to their possible beneficial effects on neuropsychological disorders. METHODS: C57BL/6J male mice were used to investigate the effect of tributyrin (TB), a prodrug of BA, on hippocampus (HIP)-dependent spatial memory, HIP synaptic transmission and plasticity mechanisms, and the expression of genes and proteins relevant to HIP glutamatergic transmission. RESULTS: Ex vivo studies, carried out in HIP slices, revealed that TB can transform early-LTP into late-LTP (l-LTP) and to rescue LTP-inhibition induced by scopolamine. The facilitation of l-LTP induced by TB was blocked both by GW9662 (a PPARγ antagonist) and C-Compound (an AMPK inhibitor), suggesting the involvement of both PPARγ and AMPK on TB effects. Moreover, 48-hour intake of a diet containing 1% TB prevented, in adolescent but not in adult mice, scopolamine-induced impairment of HIP-dependent spatial memory. In the adolescent HIP, TB upregulated gene expression levels of Pparg, leptin, and adiponectin receptors, and that of the glutamate receptor subunits AMPA-2, NMDA-1, NMDA-2A, and NMDA-2B. CONCLUSIONS: Our study shows that TB has a positive influence on LTP and HIP-dependent spatial memory, which suggests that BA may have beneficial effects on memory.


Assuntos
PPAR gama , Memória Espacial , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Quinases Ativadas por AMP/farmacologia , Animais , Ácido Butírico/metabolismo , Ácido Butírico/farmacologia , Hipocampo , Potenciação de Longa Duração/fisiologia , Masculino , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , N-Metilaspartato/metabolismo , Plasticidade Neuronal , PPAR gama/metabolismo , PPAR gama/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Derivados da Escopolamina/metabolismo , Derivados da Escopolamina/farmacologia , Memória Espacial/fisiologia , Triglicerídeos
13.
Bioorg Chem ; 124: 105826, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35487072

RESUMO

Thirty-two undescribed coumarin-monoterpenes, including the first report of six pairs of enantiomeric and twenty congeners, were isolated from the petroleum ether extract of the stems of Gerbera anandria (Linn.) Sch.-Bip. Structurally, these compounds represented C3-substituted 5-methyl-4-hydroxycoumarin-monoterpenes. Among them, 1-7 and 10-24 were rare 5-methylcoumarin-monoterpenes formed through a furan ring. Their chemical structures and absolute configurations were determined by comprehensive analysis of spectroscopic data, including HRESIMS, 1D and 2D NMR spectroscopic data, Mosher's method, ECD calculations and single crystal X-ray diffraction. Furthermore, biological studies revealed that compounds 1-3, 3a, 5, 5a, 11-12, 21-22 and 26 had the neuroprotective effects on scopolamine-induced injury in PC12 cells. Notably, 3 exhibited the strongest neuroprotective activity with the cell viability values of 77.24%. Meanwhile, pretreatment with 3 significantly downregulate apoptosis and reactive oxygen species (ROS) production, as well as strengthen antioxidant enzyme activities (MDA and SOD). Moreover, pretreatment with 3 also could attenuate the down-regulation of HO-1 and Nrf2 induced by scopolamine. In conclusion, these results demonstrated that these compounds possessed the protective effects on scopolamine-injured PC12 cells through anti-apoptotic and anti-oxidant activities.


Assuntos
Asteraceae , Fármacos Neuroprotetores , Animais , Antioxidantes , Asteraceae/química , Cumarínicos/farmacologia , Monoterpenos , Fármacos Neuroprotetores/farmacologia , Células PC12 , Ratos , Derivados da Escopolamina
14.
Cochrane Database Syst Rev ; 10: CD012715, 2022 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-36250781

RESUMO

BACKGROUND: Motion sickness is a syndrome that occurs as a result of passive body movement in response to actual motion, or the illusion of motion when exposed to virtual and moving visual environments. The most common symptoms are nausea and vomiting. Antihistamines have been used in the management of motion sickness for decades, however studies have shown conflicting results regarding their efficacy. OBJECTIVES: To assess the effectiveness of antihistamines in the prevention and treatment of motion sickness in adults and children. SEARCH METHODS: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials; Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 7 December 2021. SELECTION CRITERIA: Randomised controlled trials (RCTs) in susceptible adults and children in whom motion sickness was induced under natural conditions such as air, sea and land transportation. We also included studies in which motion sickness was induced under experimental conditions (analysed separately). Antihistamines were included regardless of class, route or dosage and compared to no treatment, placebo or any other pharmacological or non-pharmacological interventions. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were 1) the proportion of susceptible participants who did not experience any motion sickness symptoms; 2) the proportion of susceptible participants who experienced a reduction or resolution of existing symptoms. Secondary outcomes were 1) physiological measures (heart rate, core temperature and gastric tachyarrhythmia (electrogastrography)) and 2) adverse effects (sedation, impaired cognition, blurred vision). We used GRADE to assess the certainty of the evidence for each outcome. MAIN RESULTS: We included nine RCTs (658 participants). Studies were conducted across seven countries, with an overall age range of 16 to 55 years. Motion sickness was induced naturally in six studies and experimentally in four studies (rotating chair). All the naturally induced studies only evaluated first-generation antihistamines (cinnarizine and dimenhydrinate). Risk of bias across the studies varied, with mostly low risk for random sequence generation and allocation concealment, and mostly high risk for selective reporting. Only the experimentally induced studies measured physiological parameters and only the naturally induced studies evaluated adverse effects. There were no studies that clearly assessed the paediatric population. Antihistamines versus placebo or no treatment Antihistamines are probably more effective than placebo at preventing motion sickness symptoms under natural conditions (symptoms prevented: 25% placebo; 40% antihistamines) (risk ratio (RR) 1.81, 95% confidence interval (CI) 1.23 to 2.66; 3 studies; 240 participants) (moderate-certainty). The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under experimental conditions (standardised mean difference (SMD) 0.32, 95% CI -0.18 to 0.83; 2 studies; 62 participants) (very low-certainty). No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia under experimental conditions (mean difference (MD) -2.2, 95% CI -11.71 to 7.31; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. When compared to placebo, antihistamines may be more likely to cause sedation (sedation: 44% placebo; 66% antihistamines) (RR 1.51, 95% CI 1.12 to 2.02; 2 studies; 190 participants) (low-certainty); they may result in little or no difference in blurred vision (blurred vision: 12.5% placebo; 14% antihistamines) (RR 1.14, 95% CI 0.53 to 2.48; 2 studies; 190 participants) (low-certainty); and they may result in little or no difference in terms of impaired cognition (impaired cognition: 33% placebo; 29% antihistamines) (RR 0.89, 95% CI 0.58 to 1.38; 2 studies; 190 participants) (low-certainty). Antihistamines versus scopolamine The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under natural conditions when compared to scopolamine (symptoms prevented: 81% scopolamine; 71% antihistamines) (RR 0.89, 95% CI 0.68 to 1.16; 2 studies; 71 participants) (very low-certainty). No studies were performed under experimental conditions. No studies reported results on the resolution of existing motion sickness symptoms. The evidence is very uncertain about the effect of antihistamines on heart rate under natural conditions (narrative report, 1 study; 20 participants; "No difference in pulse frequency"; very low-certainty). No studies reported results for any other physiological measures. When compared to scopolamine, the evidence is very uncertain about the effect of antihistamines on sedation (sedation: 21% scopolamine; 30% antihistamines) (RR 0.82, 95% CI 0.07 to 9.25; 2 studies; 90 participants) (very low-certainty) and on blurred vision (narrative report: not a significant difference; 1 study; 51 participants; very low-certainty). No studies evaluated impaired cognition. Antihistamines versus antiemetics Antihistamines may result in little or no difference in the prevention of motion sickness under experimental conditions (MD -0.20, 95% CI -10.91 to 10.51; 1 study; 42 participants) (low-certainty). The evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. No studies assessed the effects of antihistamines versus antiemetics under natural conditions. No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. No studies evaluated sedation, impaired cognition or blurred vision. One study reported physiological data for this outcome, evaluating gastric tachyarrhythmia specifically. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants; low-certainty evidence). This evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. Antihistamines versus acupuncture The evidence is very uncertain about the effects of antihistamines on the prevention of motion sickness under experimental conditions when compared to acupuncture (RR 1.32, 95% CI 1.12 to 1.57; 1 study; 100 participants) (very low-certainty). This study did not assess the prevention of motion sickness under natural conditions, nor the resolution of existing motion sickness symptoms. There was no study performed under natural conditions. Physiological measures and adverse effects were not reported. AUTHORS' CONCLUSIONS: There is probably a reduction in the risk of developing motion sickness symptoms under naturally occurring conditions of motion when using first-generation antihistamines, in motion sickness-susceptible adults, compared to placebo. Antihistamines may be more likely to cause sedation when compared to placebo. No studies evaluated the treatment of existing motion sickness, and there are few data on the effect of antihistamines in children. The evidence for all other outcomes and comparisons (versus scopolamine, antiemetics and acupuncture) was of low or very low certainty and we are therefore uncertain about these effects of antihistamines.


Assuntos
Antieméticos , Cinarizina , Dimenidrinato , Enjoo devido ao Movimento , Adolescente , Adulto , Criança , Antagonistas dos Receptores Histamínicos/uso terapêutico , Humanos , Pessoa de Meia-Idade , Enjoo devido ao Movimento/tratamento farmacológico , Derivados da Escopolamina , Adulto Jovem
15.
Cochrane Database Syst Rev ; 5: CD006981, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35593746

RESUMO

BACKGROUND: Motor neuron disease (MND), also known as amyotrophic lateral sclerosis (ALS), is a progressive neurodegenerative condition that may cause dysphagia, as well as limb weakness, dysarthria, emotional lability, and respiratory failure. Since normal salivary production is 0.5 L to 1.5 L daily, loss of salivary clearance due to dysphagia leads to salivary pooling and sialorrhea, often resulting in distress and inconvenience to people with MND. This is an update of a review first published in 2011. OBJECTIVES: To assess the effects of treatments for sialorrhea in MND, including medications, radiotherapy and surgery. SEARCH METHODS: On 27 August 2021, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, AMED, CINAHL, ClinicalTrials.gov and the WHO ICTRP. We checked the bibliographies of the identified randomized trials and contacted trial authors as needed. We contacted known experts in the field to identify further published and unpublished papers. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs, including cross-over trials, on any intervention for sialorrhea and related symptoms, compared with each other, placebo or no intervention, in people with ALS/MND. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We identified four RCTs involving 110 participants with MND who were described as having intractable sialorrhea or bulbar dysfunction. A well-designed study of botulinum toxin B compared to placebo injected into the parotid and submandibular glands of 20 participants showed that botulinum toxin B may produce participant-reported improvement in sialorrhea, but the confidence interval (CI) was also consistent with no effect. Six of nine participants in the botulinum group and two of nine participants in the placebo group reported improvement (risk ratio (RR) 3.00, 95% CI 0.81 to 11.08; 1 RCT; 18 participants; low-certainty evidence). An objective measure indicated that botulinum toxin B probably reduced saliva production (in mL/5 min) at eight weeks compared to placebo (MD -0.50, 95% CI -1.07 to 0.07; 18 participants, moderate-certainty evidence). Botulinum toxin B may have little to no effect on quality of life, measured on the Schedule for Evaluation of Individual Quality of Life direct weighting scale (SEIQoL-DW; 0-100, higher values indicate better quality of life) (MD -2.50, 95% CI -17.34 to 12.34; 1 RCT; 17 participants; low-certainty evidence). The rate of adverse events may be similar with botulinum toxin B and placebo (20 participants; low-certainty evidence). Trialists did not consider any serious events to be related to treatment. A randomized pilot study of botulinum toxin A or radiotherapy in 20 participants, which was at high risk of bias, provided very low-certainty evidence on the primary outcome of the Drool Rating Scale (DRS; range 8 to 39 points, higher scores indicate worse drooling) at 12 weeks (effect size -4.8, 95% CI -10.59 to 0.92; P = 0.09; 1 RCT; 16 participants). Quality of life was not measured. Evidence for adverse events, measured immediately after treatment (RR 7.00, 95% CI 1.04 to 46.95; 20 participants), and after four weeks (when two people in each group had viscous saliva) was also very uncertain. A phase 2, randomized, placebo-controlled cross-over study of 20 mg dextromethorphan hydrobromide and 10 mg quinidine sulfate (DMQ) found that DMQ may produce a participant-reported improvement in sialorrhea, indicated by a slight improvement (decrease) in mean scores for the primary outcome, the Center for Neurologic Study Bulbar Function Scale (CNS-BFS). Mean total CNS-BFS (range 21 (no symptoms) to 112 (maximum symptoms)) was 53.45 (standard error (SE) 1.07) for the DMQ treatment period and 59.31 (SE 1.10) for the placebo period (mean difference) MD -5.85, 95% CI -8.77 to -2.93) with a slight decrease in the CNS-BFS sialorrhea subscale score (range 7 (no symptoms) to 35 (maximum symptoms)) compared to placebo (MD -1.52, 95% CI -2.52 to -0.52) (1 RCT; 60 participants; moderate-certainty evidence). The trial did not report an objective measure of saliva production or measure quality of life. The study was at an unclear risk of bias. Adverse events were similar to other trials of DMQ, and may occur at a similar rate as placebo (moderate-certainty evidence, 60 participants), with the most common side effects being constipation, diarrhea, nausea, and dizziness. Nausea and diarrhea on DMQ treatment resulted in one withdrawal. A randomized, double-blind, placebo-controlled cross-over study of scopolamine (hyoscine), administered using a skin patch, involved 10 randomized participants, of whom eight provided efficacy data. The participants were unrepresentative of clinic cohorts under routine clinical care as they had feeding tubes and tracheostomy ventilation, and the study was at high risk of bias. The trial provided very low-certainty evidence on sialorrhea in the short term (7 days' treatment, measured on the Amyotrophic Lateral Scelerosis Functional Rating Scale-Revised (ALSFRS-R) saliva item (P = 0.572)), and the amount of saliva production in the short term, as indicated by the weight of a cotton roll (P = 0.674), or daily oral suction volume (P = 0.69). Quality of life was not measured. Adverse events evidence was also very uncertain. One person treated with scopolamine had a dry mouth and one died of aspiration pneumonia considered unrelated to treatment. AUTHORS' CONCLUSIONS: There is some low-certainty or moderate-certainty evidence for the use of botulinum toxin B injections to salivary glands and moderate-certainty evidence for the use of oral dextromethorphan with quinidine (DMQ) for the treatment of sialorrhea in MND. Evidence on radiotherapy versus botulinum toxin A injections, and scopolamine patches is too uncertain for any conclusions to be drawn. Further research is required on treatments for sialorrhea. Data are needed on the problem of sialorrhea in MND and its measurement, both by participant self-report measures and objective tests. These will allow the development of better RCTs.


Assuntos
Esclerose Lateral Amiotrófica , Toxinas Botulínicas Tipo A , Transtornos de Deglutição , Doença dos Neurônios Motores , Sialorreia , Esclerose Lateral Amiotrófica/complicações , Toxinas Botulínicas Tipo A/uso terapêutico , Ensaios Clínicos Fase II como Assunto , Transtornos de Deglutição/complicações , Transtornos de Deglutição/etiologia , Diarreia/complicações , Humanos , Doença dos Neurônios Motores/complicações , Náusea , Ensaios Clínicos Controlados Aleatórios como Assunto , Saliva , Derivados da Escopolamina , Sialorreia/tratamento farmacológico , Sialorreia/etiologia
16.
Int J Mol Sci ; 23(21)2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36362360

RESUMO

The gut microbiota has been demonstrated to play a critical role in maintaining cognitive function via the gut-brain axis, which may be related to the parasympathetic nervous system (PNS). However, the exact mechanism remains to be determined. We investigated that patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) could exhibit an altered gut microbiota through the suppression of the PNS, compared to the healthy individuals, using the combined gut microbiota data from previous human studies. The hypothesis was validated in rats to suppress the PNS by scopolamine injections. The human fecal bacterial FASTA/Q files were selected and combined from four different AD studies (n = 410). All rats had a high-fat diet and treatments for six weeks. The MD rats had memory impairment by scopolamine injection (2 mg/kg body weight; MD, Control) or no memory impairment by saline injection. The scopolamine-injected rats had a donepezil intake as the positive group. In the optimal model generated from the XGboost analysis, Blautia luti, Pseudomonas mucidoiens, Escherichia marmotae, and Gemmiger formicillis showed a positive correlation with MCI while Escherichia fergusonii, Mycobacterium neglectum, and Lawsonibacter asaccharolyticus were positively correlated with AD in the participants with enterotype Bacteroides (ET-B, n = 369). The predominant bacteria in the AD group were negatively associated in the networking analysis with the bacteria in the healthy group of ET-B participants. From the animal study, the relative abundance of Bacteroides and Bilophilia was lower, and that of Escherichia, Blautia, and Clostridium was higher in the scopolamine-induced memory deficit (MD) group than in the normal group. These results suggest that MCI was associated with the PNS suppression and could progress to AD by exacerbating the gut dysbiosis. MCI increased Clostridium and Blautia, and its progression to AD elevated Escherichia and Pseudomonas. Therefore, the modulation of the PNS might be linked to an altered gut microbiota and brain function, potentially through the gut-brain axis.


Assuntos
Doença de Alzheimer , Microbioma Gastrointestinal , Humanos , Animais , Ratos , Microbioma Gastrointestinal/fisiologia , Transtornos da Memória/etiologia , Bactérias , Sistema Nervoso Parassimpático , Derivados da Escopolamina
17.
Med J Malaysia ; 77(4): 481-487, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35902939

RESUMO

OBJECTIVE: This study assessed the delivery of tiotropium via Respimat® in addition to standard care of treatment among chronic obstructive pulmonary disease (COPD) patients. We study the efficacy, clinical outcome of handling inhaler device, rate of exacerbation and frequency of hospital admission of tiotropium via Respimat® with and without the use of a spacer (AeroChamber®). METHODS: Randomised, open-label study of COPD patients which was randomised into two groups: spacer or nonspacer groups using tiotropium via Respimat®. Treatment with their pre-existing inhalers continued. Subjects were assessed at weeks 0, and 8 for forced expiratory volume in 1 second (FEV1), COPD assessment tool (CAT), St. George's Respiratory Questionnaire (SGRQ), and satisfaction questionnaire. RESULTS: We enrolled 96 subjects: 49 in the spacer group and 47 in the non-spacer group. The mean predicted FEV1 in spacer group was 54.48% at baseline and 57.5l% at week 8: p=0.011. In the non-spacer groups, FEV1 was 54.48% at baseline and 59.20% with a mean increment of 4.72 in both groups: p=0.002. There were no difference of exacerbation rates and hospital admission between both groups. At baseline, mean CAT score in the spacer group was 14.01 which improved to 9.80 (p<0.001) and 14.01 to 8.80 (p<0.001) in the non-spacer group. SGRQ total score reduced in both groups with mean difference of 3.1 (p<0.001) and 3.7: (p<0.001) at weeks 0 to 8. CONCLUSION: There was no difference between exacerbation and hospital admissions between both groups. There was no difference in FEV1, CAT and SQRQ score using Tiotropium via Respimat® with or without a spacer.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Derivados da Escopolamina , Broncodilatadores/uso terapêutico , Humanos , Satisfação do Paciente , Satisfação Pessoal , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Derivados da Escopolamina/efeitos adversos , Brometo de Tiotrópio/efeitos adversos , Resultado do Tratamento
18.
Wiad Lek ; 75(2): 473-477, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35307679

RESUMO

OBJECTIVE: The aim: To evaluate the dynamics of the interferon and collagen-IV systems in bronchoalveolar lavage in the treatment of chronic obstructive pulmonary disease using the tiotropium bromide medication. PATIENTS AND METHODS: Materials and methods: The study involved 60 COPD patients with bronchial obstruction of the II degree before and on days 30 and 60 of therapy using conventional treatment regimens and inhalations of tiotropium bromide a the dose of 18 mcg once a day. The collagen-IV levels in bronchoalveolar fluid were determined by means of enzyme-linked immunoassay using "StatFax 303 Plus" analyzer and "Biotrin Collagen IV EIA" reagents. The level of IFN-γ was identified with the help of enzyme-linked immunoassay using "StatFax 303 Plus" analyzer and "ProKon" reagents (LLC "Protein Contour", Russia) in bronchoalveolar fluid obtained during fiber-optic bronchoscopy. RESULTS: Results: When examining Group I patients on the 30th day we found out that the content of collagen-IV in the bronchoalveolar fluid had decreased by only 10.29% (p <0.05). Detection of collagen-IV indices in Group II patients on the 30th day of tiotropium bromide use showed the 29.43% (p <0.05) decrease in its content as compared to the initial indices. In Group III patients, the concentration of collagen-IV had a maximum tendency to normalize and made up (24.72 ± 1.15) ng/ml, and decreased by 2.44 times (p <0.05) as compared to the initial indices. Our examination of 12 patients from the comparison group I on the 60th day of treatment revealed even a slight increase in the content of collagen-IV in the bronchoalveolar fluid, as compared with the data obtained on the 30th day. The identified IFN-γ deficiency is indicative for the COPD of the II degree of bronchial obstruction, and its indices were 2.29 times lower than those observed in people from the control group. On day 30, we found out that the content of IFN-γ in Group I patients increased by only 10.29% (p>0.05). Detection of IFN-γ in Group II patients showed 42.27% (p<0,05) increase in its content as compared to the initial indices. The most favorable dynamics of IFN-γ levels in bronchoalveolar contents was observed in Group III patients, and at the time of observation it made up (1.16 ± 0.08) pg/ml, having 2 times (p<0.05) increased as compared to the initial indices. However, in contrast to those taking tiotropium bromide, we examined 12 patients from Group I on the 60th day of treatment and found no significant positive dynamics of IFN-γ content in bronchoalveolar fluid as compared to the indices obtained on day 30. CONCLUSION: Conclusions: The obtained findings indicate the effect of tiotropium bromide on the reduction of interferon-γ and reduce of collagen-IV levels, which depend on the duration of its use.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Derivados da Escopolamina , Lavagem Broncoalveolar , Broncodilatadores/uso terapêutico , Humanos , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Derivados da Escopolamina/efeitos adversos , Derivados da Escopolamina/uso terapêutico , Brometo de Tiotrópio/uso terapêutico
19.
Pharmacology ; 105(7-8): 369-376, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31655826

RESUMO

INTRODUCTION: Benzodiazepine anxiolytics are believed to cause urination disorders due to their anticholinergic effects. OBJECTIVE: This study was carried out to investigate the potential inhibitory effects of 15 clinically available anxiolytics in Japan on acetylcholine (ACh)-induced contractions in rat detrusor smooth muscle (DSM) to predict whether these anxiolytics could induce urination disorders. METHODS: -Effects of anxiolytics on contractions induced by ACh and 80 mmol/L KCl solution in rat DSM and effects of anxiolytics on specific binding of [N-methyl-3H]scopolamine ([3H]NMS) in mouse cerebral cortex were investigated. RESULTS AND CONCLUSIONS: ACh-induced contractions in rat DSM were inhibited by clotiazepam and diazepam (benzodiazepine anxiolytics) at concentrations that were clinically relevant. These contractions were also significantly inhibited by paroxetine, escitalopram (selective serotonin reuptake inhibitors -[SSRIs]), and hydroxyzine (a histamine H1 receptor antagonist), albeit at concentrations that substantially exceeded clinically achievable blood levels. At a concentration of 10-5 mol/L, paroxetine, escitalopram, and hydroxyzine inhibited 80 mmol/L high-KCl solution-induced rat DSM contractions but not clotiazepam and diazepam. Paroxetine, escitalopram, and hydroxyzine also inhibited specific binding of [3H]NMS in mouse cerebral cortex but clotiazepam and diazepam did not. In contrast to the effects of the abovementioned anxiolytics, ACh-induced contractions were not significantly affected by tofisopam, alprazolam, lorazepam, bromazepam, oxazolam, chlordiazepoxide, clonazepam, ethyl loflazepate (benzodiazepine anxiolytics), fluvoxamine (an SSRI), or tandospirone (a serotonin 5-HT1A receptor agonist). These findings suggest that most clinically used anxiolytics are not likely to result in anticholinergic-induced urination disorders within their clinically achievable blood concentration ranges. However, clotiazepam and diazepam may induce urination disorders within their clinical dose ranges via nonanticholinergic inhibition of DSM contractility.


Assuntos
Acetilcolina/antagonistas & inibidores , Ansiolíticos/toxicidade , Benzodiazepinas/toxicidade , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Bexiga Urinária/efeitos dos fármacos , Animais , Masculino , Camundongos , Contração Muscular/fisiologia , Músculo Liso/fisiologia , Ratos , Ratos Wistar , Derivados da Escopolamina/metabolismo , Bexiga Urinária/fisiologia , Transtornos Urinários/induzido quimicamente
20.
Nature ; 482(7386): 552-6, 2012 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-22358844

RESUMO

Acetylcholine, the first neurotransmitter to be identified, exerts many of its physiological actions via activation of a family of G-protein-coupled receptors (GPCRs) known as muscarinic acetylcholine receptors (mAChRs). Although the five mAChR subtypes (M1-M5) share a high degree of sequence homology, they show pronounced differences in G-protein coupling preference and the physiological responses they mediate. Unfortunately, despite decades of effort, no therapeutic agents endowed with clear mAChR subtype selectivity have been developed to exploit these differences. We describe here the structure of the G(q/11)-coupled M3 mAChR ('M3 receptor', from rat) bound to the bronchodilator drug tiotropium and identify the binding mode for this clinically important drug. This structure, together with that of the G(i/o)-coupled M2 receptor, offers possibilities for the design of mAChR subtype-selective ligands. Importantly, the M3 receptor structure allows a structural comparison between two members of a mammalian GPCR subfamily displaying different G-protein coupling selectivities. Furthermore, molecular dynamics simulations suggest that tiotropium binds transiently to an allosteric site en route to the binding pocket of both receptors. These simulations offer a structural view of an allosteric binding mode for an orthosteric GPCR ligand and provide additional opportunities for the design of ligands with different affinities or binding kinetics for different mAChR subtypes. Our findings not only offer insights into the structure and function of one of the most important GPCR families, but may also facilitate the design of improved therapeutics targeting these critical receptors.


Assuntos
Receptor Muscarínico M3/química , Receptor Muscarínico M3/metabolismo , Acetilcolina/química , Acetilcolina/metabolismo , Sítio Alostérico , Animais , Células COS , Cristalização , Cristalografia por Raios X , Cinética , Ligantes , Modelos Moleculares , Simulação de Dinâmica Molecular , Ensaio Radioligante , Ratos , Derivados da Escopolamina/química , Derivados da Escopolamina/metabolismo , Especificidade por Substrato , Brometo de Tiotrópio
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