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1.
Biochem Pharmacol ; 162: 41-54, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30529689

RESUMO

Although the proteasome inhibitor (PI) bortezomib (Btz) is in current clinical use as a front-line treatment for multiple myeloma, its clinical efficacy in solid tumors has not been satisfactory. Here, we show that loperamide (Lop), an antidiarrheal drug, effectively sensitizes various colon cancer cells, but not normal epithelial cells, to PI-mediated cell death. We report that combined treatment with Btz and Lop induces paraptosis-like cell death accompanied by severe endoplasmic reticulum (ER)-derived vacuolation. Furthermore, Lop potentiates Btz-mediated ER stress and ER dilation due to misfolded protein accumulation and Ca2+ imbalance, leading to CHOP upregulation and subsequent paraptosis-like cell death. Taken together, our results show for the first time that a combined regimen of PI and Lop may provide an effective and safe therapeutic strategy against solid tumors, including colon cancer, by enhancing the sensitivity to PIs and reducing the side effects of such treatment.


Assuntos
Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Bortezomib/farmacologia , Neoplasias do Colo/patologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Loperamida/farmacologia , Antidiarreicos/farmacologia , Apoptose/fisiologia , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Ciclofosfamida/farmacologia , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Células HCT116 , Células HeLa , Humanos , Prednisona/farmacologia , Inibidores de Proteassoma/farmacologia , Vincristina/farmacologia
3.
J Phys Chem B ; 122(49): 11571-11578, 2018 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-30247032

RESUMO

We present a simple approach to calculate the kinetic properties of lipid membrane crossing processes from biased molecular dynamics simulations. We demonstrate that by using biased simulations, one can obtain highly accurate kinetic information with significantly reduced computational time with respect to unbiased simulations. We describe how to conveniently calculate the transition rates to enter, cross, and exit the membrane in terms of the mean first passage times. To obtain free energy barriers and relaxation times from biased simulations only, we constructed Markov models using the dynamic histogram analysis method (DHAM). The permeability coefficients that are calculated from the relaxation times are found to correlate highly with experimentally evaluated values. We show that more generally, certain calculated kinetic properties linked to the crossing of the membrane layer (e.g., barrier height and barrier crossing rates) are good indicators of ordering drugs by permeability. Extending the analysis to a 2D Markov model provides a physical description of the membrane crossing mechanism.


Assuntos
Permeabilidade da Membrana Celular/efeitos dos fármacos , Simulação de Dinâmica Molecular , Clorpromazina/química , Clorpromazina/farmacologia , Desipramina/química , Desipramina/farmacologia , Domperidona/química , Domperidona/farmacologia , Cinética , Labetalol/química , Labetalol/farmacologia , Bicamadas Lipídicas/química , Loperamida/química , Loperamida/farmacologia , Estrutura Molecular , Propranolol/química , Propranolol/farmacologia , Termodinâmica , Verapamil/química , Verapamil/farmacologia
4.
Cell Death Dis ; 9(10): 994, 2018 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-30250198

RESUMO

Autophagy is a well-described degradation mechanism that promotes cell survival upon nutrient starvation and other forms of cellular stresses. In addition, there is growing evidence showing that autophagy can exert a lethal function via autophagic cell death (ACD). As ACD has been implicated in apoptosis-resistant glioblastoma (GBM), there is a high medical need for identifying novel ACD-inducing drugs. Therefore, we screened a library containing 70 autophagy-inducing compounds to induce ATG5-dependent cell death in human MZ-54 GBM cells. Here, we identified three compounds, i.e. loperamide, pimozide, and STF-62247 that significantly induce cell death in several GBM cell lines compared to CRISPR/Cas9-generated ATG5- or ATG7-deficient cells, pointing to a death-promoting role of autophagy. Further cell death analyses conducted using pharmacological inhibitors revealed that apoptosis, ferroptosis, and necroptosis only play minor roles in loperamide-, pimozide- or STF-62247-induced cell death. Intriguingly, these three compounds induce massive lipidation of the autophagy marker protein LC3B as well as the formation of LC3B puncta, which are characteristic of autophagy. Furthermore, loperamide, pimozide, and STF-62247 enhance the autophagic flux in parental MZ-54 cells, but not in ATG5 or ATG7 knockout (KO) MZ-54 cells. In addition, loperamide- and pimozide-treated cells display a massive formation of autophagosomes and autolysosomes at the ultrastructural level. Finally, stimulation of autophagy by all three compounds is accompanied by dephosphorylation of mammalian target of rapamycin complex 1 (mTORC1), a well-known negative regulator of autophagy. In summary, our results indicate that loperamide, pimozide, and STF-62247 induce ATG5- and ATG7-dependent cell death in GBM cells, which is preceded by a massive induction of autophagy. These findings emphasize the lethal function and potential clinical relevance of hyperactivated autophagy in GBM.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Loperamida/farmacologia , Pimozida/farmacologia , Piridinas/farmacologia , Tiazóis/farmacologia , Autofagossomos/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/ultraestrutura , Linhagem Celular Tumoral , Endossomos/metabolismo , Glioblastoma/patologia , Glioblastoma/ultraestrutura , Células HT29 , Humanos , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Microscopia Eletrônica , Proteínas Associadas aos Microtúbulos/metabolismo , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo
5.
Drug Des Devel Ther ; 12: 2403-2411, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30122898

RESUMO

Purpose: To investigate the therapeutic effects of protease-activated receptor 2 (PAR-2) agonist SLIGRL-NH2 on loperamide-induced Sprague-Dawley (SD) rat constipation animal models. Materials and methods: Loperamide was injected subcutaneously to induce constipation twice a day for 3 days. SD rats (n = 30) were randomly divided into five groups: non-constipation group (control, n = 6), constipation group (constipation, n = 6), constipation + SLIGRL-NH2 low-dosage group (SLIGRL-NH2 low, n=6), constipation + SLIGRL-NH2 high-dosage group (SLIGRL-NH2 high, n = 6), and constipation + prucalopride (positive control, n = 6). The SLIGRL-NH2 low group and SLIGRL-NH2 high group were administered with 2.5 µmol/kg and 5 µmol/kg SLIGRL-NH2, respectively, and the prucalopride group received 2 mg/kg prucalopride. The control and constipation group received 1× PBS under the same pattern. SLIGRL-NH2 and prucalopride were orally administrated once daily for 7 days. On the final day of oral administration, food intake, water intake, the number of stool pellets, weight, and fecal water content was calculated; moreover, the colons of rats in different groups were collected and histological features were examined by hematoxylin and eosin staining; furthermore, the expression of anoctamin-1 was determined by Immunohistochemical methods, and the expressions of c-kit and PAR-2 were examined using real-time quantitative polymerase chain reaction and Western blot methods; finally, the expressions of neurotransmitter vasoactive intestinal peptide (VIP) and substance P (SP) were examined using enzyme-linked immuno-sorbent assay methods. Results: The feeding and excretion behaviors, intestinal transit ratio, and the histological feature of the colon in the constipated rats were all improved by SLIGRL-NH2 treatment; moreover, SLIGRL-NH2 treatment induced significant increase in the expression of PAR-2 and also increased number of interstitial Cajal cells. Furthermore, SLIGRL-NH2 also decreased the contents of the inhibitory neurotransmitter VIP and increased the expression of the excitatory neurotransmitter SP. High dose of SLIGRL-NH2 has shown similar anti-constipation effects as prucalopride. Conclusion: These results suggested that SLIGRL-NH2 can enhance gastrointestinal transit and alleviate in rats with loperamide-induced constipation.


Assuntos
Constipação Intestinal/tratamento farmacológico , Loperamida/farmacologia , Oligopeptídeos/uso terapêutico , Receptor PAR-2/agonistas , Animais , Constipação Intestinal/induzido quimicamente , Constipação Intestinal/patologia , Constipação Intestinal/fisiopatologia , Modelos Animais de Doenças , Trânsito Gastrointestinal/efeitos dos fármacos , Masculino , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Substância P/análise
6.
JCI Insight ; 3(14)2018 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-30046015

RESUMO

SLC26A3 (downregulated in adenoma; DRA) is a Cl-/anion exchanger expressed in the luminal membrane of intestinal epithelial cells, where it facilitates electroneutral NaCl absorption. SLC26A3 loss of function in humans or mice causes chloride-losing diarrhea. Here, we identified slc26a3 inhibitors in a screen of 50,000 synthetic small molecules done in Fischer rat thyroid (FRT) cells coexpressing slc26a3 and a genetically encoded halide sensor. Structure-activity relationship studies were done on the most potent inhibitor classes identified in the screen: 4,8-dimethylcoumarins and acetamide-thioimidazoles. The dimethylcoumarin DRAinh-A250 fully and reversibly inhibited slc26a3-mediated Cl- exchange with HCO3-, I-, and thiocyanate (SCN-), with an IC50 of ~0.2 µM. DRAinh-A250 did not inhibit the homologous anion exchangers slc26a4 (pendrin) or slc26a6 (PAT-1), nor did it alter activity of other related proteins or intestinal ion channels. In mice, intraluminal DRAinh-A250 blocked fluid absorption in closed colonic loops but not in jejunal loops, while the NHE3 (SLC9A3) inhibitor tenapanor blocked absorption only in the jejunum. Oral DRAinh-A250 and tenapanor comparably reduced signs of constipation in loperamide-treated mice, with additive effects found on coadministration. DRAinh-A250 was also effective in loperamide-treated cystic fibrosis mice. These studies support a major role of slc26a3 in colonic fluid absorption and suggest the therapeutic utility of SLC26A3 inhibition in constipation.


Assuntos
Antiporters/farmacologia , Constipação Intestinal/tratamento farmacológico , Transportadores de Sulfato/antagonistas & inibidores , Transportadores de Sulfato/metabolismo , Animais , Antiporters/antagonistas & inibidores , Antiporters/química , Antiporters/genética , Antiporters/metabolismo , Antiportadores de Cloreto-Bicarbonato/farmacologia , Cloretos/metabolismo , Fibrose Cística , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células HEK293 , Ensaios de Triagem em Larga Escala , Humanos , Transporte de Íons , Loperamida/farmacologia , Camundongos , Ratos , Ratos Endogâmicos F344 , Trocador 3 de Sódio-Hidrogênio/farmacologia , Transportadores de Sulfato/genética , Transportadores de Sulfato/farmacologia
7.
Elife ; 72018 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-29932421

RESUMO

The intrinsic efficacy of orthosteric ligands acting at G-protein-coupled receptors (GPCRs) reflects their ability to stabilize active receptor states (R*) and is a major determinant of their physiological effects. Here, we present a direct way to quantify the efficacy of ligands by measuring the binding of a R*-specific biosensor to purified receptor employing interferometry. As an example, we use the mu-opioid receptor (µ-OR), a prototypic class A GPCR, and its active state sensor, nanobody-39 (Nb39). We demonstrate that ligands vary in their ability to recruit Nb39 to µ-OR and describe methadone, loperamide, and PZM21 as ligands that support unique R* conformation(s) of µ-OR. We further show that positive allosteric modulators of µ-OR promote formation of R* in addition to enhancing promotion by orthosteric agonists. Finally, we demonstrate that the technique can be utilized with heterotrimeric G protein. The method is cell-free, signal transduction-independent and is generally applicable to GPCRs.


Assuntos
Técnicas Biossensoriais , Interferometria/métodos , Receptores Opioides mu/análise , Bibliotecas de Moléculas Pequenas/farmacologia , Regulação Alostérica , Sítio Alostérico , Biotina/química , Humanos , Ligantes , Loperamida/metabolismo , Loperamida/farmacologia , Metadona/metabolismo , Metadona/farmacologia , Ligação Proteica , Receptores Opioides mu/metabolismo , Sensibilidade e Especificidade , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/metabolismo , Bibliotecas de Moléculas Pequenas/metabolismo , Soluções , Estreptavidina/química , Tiofenos/metabolismo , Tiofenos/farmacologia , Ureia/análogos & derivados , Ureia/metabolismo , Ureia/farmacologia
8.
Benef Microbes ; 9(3): 453-464, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29633634

RESUMO

Constipation has a significant influence on quality of life. Patients with constipation have slow waves in their gastrointestinal smooth muscles and less faecal water contents, which are closely associated with down-regulation of the interstitial cells of Cajal (ICC) in the gastrointestinal muscles and the aquaporin protein AQP3 expressed in colon epithelial cells. Recent studies supported that patients with constipation have altered intestinal microbial structures compared with healthy controls. Intestinal dysbiosis might be one possible pathophysiological mechanism causing constipation. Bacterial strains, such as Lactobacillus spp., have shown many beneficial effects on the amelioration of constipation. However, few studies reported the structural changes of intestinal microbiota post-intervention of probiotics. In this study, a bacterial mixture was administrated to rats with loperamide-induced constipation. Effects of the bacterial mixture on small intestine transit (SIT), faecal water content, and the intestinal microbiome in rats were evaluated. Meanwhile, we investigated several factors involved in signalling pathways that regulate function of ICC and expression of AQP3 to discuss the possible underlying molecular mechanisms. Intervention of the bacterial mixture improved SIT and faecal water content in constipated rats. The up-regulation of C-kit/SP signalling pathways in ICC and AQP3 significantly contributed to improvements. These changes were closely associated with the manipulation of intestinal dysbiosis in constipated rats. Furthermore, our results revealed the important role of intestinal microbiota in affecting gut motility through regulation of serotonin biosynthesis. This monoamine neurotransmitter, secreted from enterochromaffin cells, up-regulated both substance P/neurokinin 1 receptors pathway of ICC and the expression of AQP3 in intestinal epithelial cells. Our study suggested that the disrupted microbiome in patients could be a potential therapeutic target for the improvement of constipation.


Assuntos
Constipação Intestinal/complicações , Disbiose/terapia , Probióticos/administração & dosagem , Animais , Antidiarreicos/administração & dosagem , Antidiarreicos/farmacologia , Constipação Intestinal/induzido quimicamente , Fezes/química , Microbioma Gastrointestinal , Trânsito Gastrointestinal , Intestino Delgado/fisiologia , Loperamida/administração & dosagem , Loperamida/farmacologia , Ratos , Resultado do Tratamento , Água/análise
9.
Endocr Regul ; 52(4): 185-191, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31517614

RESUMO

OBJECTIVE: This study investigated whether the metformin (Met)-induced enhanced intestinal uptake of 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) is reduced by loperamide, a long-acting anti-diarrheal agent. METHODS: Mean 18F-FDG uptake in the mouse small intestine and colon with Met exposure was compared with that in control mice. In the Met group, high-dose (1.0 mg/kg body weight) and low-dose (0.1 mg/kg body weight) loperamide were introduced, and 18F-FDG uptake in the small intestine and colon was compared with that of control mice administered high-dose loperamide. The percent injected dose of 18F-FDG per gram of tissue (%ID/g) in the extracted tissues was then determined. RESULTS: 18F-FDG uptake increased significantly in the small intestine (0.64±0.06 vs. 1.01±0.15, p=0.040) and, especially, the colon (0.46±0.13 vs. 2.16±0.51, p<0.001) after Met exposure. Neither high-dose nor low-dose loperamide significantly reduced 18F-FDG uptake in the small intestine (0.82±0.31 vs. 0.84±0.22, p=0.93 and 0.78±0.25 vs. 0.70±0.15, p=0.13, respectively) or colon (2.13±0.41 vs. 1.67±0.55, p=0.063 and 1.77±0.39 vs. 1.80±0.25, p=0.56, respectively). The colonic %ID/g was significantly higher in Met groups irrespective of loperamide introduction than in control group, whereas the significant difference in the small intestine was observed only between Met and control groups. CONCLUSION: Metformin increased 18F-FDG uptake in intestines especially in colon. Loperamide administration partially, but not sufficiently, suppresses the Met-induced increased colonic uptake of 18F-FDG.


Assuntos
Fluordesoxiglucose F18/farmacocinética , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Intestinos/efeitos dos fármacos , Loperamida/farmacologia , Metformina/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Interações Medicamentosas , Mucosa Intestinal/diagnóstico por imagem , Intestinos/diagnóstico por imagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons
10.
Anesth Analg ; 126(4): 1369-1376, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29261544

RESUMO

BACKGROUND: Previous studies have demonstrated the participation of peripheral µ-opioid receptors (MOR) in the antinociceptive effect of systemically administered morphine and loperamide in an orofacial muscle pain model, induced by hypertonic saline, but not in a spinally innervated one, in rats. In this study, we determine whether this peripheral antinociceptive effect is due to the activation of MOR localized in the muscle, ganglia, or both. METHODS: To determine the local antinociceptive effect of morphine and loperamide, 2 models of acute muscle pain (trigeminal and spinal) were used. Also, to study the MOR expression, protein quantification was performed in the trigeminal and spinal ganglia, and in the muscles. RESULTS: The behavioral results show that the intramuscular injection of morphine and loperamide did not exert an antinociceptive effect in either muscle (morphine: P = .63, loperamide: P = .9). On the other hand, MOR expression was found in the ganglia but not in the muscles. This expression was on average 44% higher (95% confidence interval, 33.3-53.9) in the trigeminal ganglia than in the spinal one. CONCLUSIONS: The peripheral antinociceptive effect of systemically administered opioids may be due to the activation of MOR in ganglia. The greater expression of MOR in trigeminal ganglia could explain the higher antinociceptive effect of opioids in orofacial muscle pain than in spinal muscle pain. Therefore, peripheral opioids could represent a promising approach for the treatment of orofacial pain.


Assuntos
Dor Aguda/tratamento farmacológico , Analgésicos/farmacologia , Dor Facial/tratamento farmacológico , Gânglios Espinais/efeitos dos fármacos , Loperamida/farmacologia , Morfina/farmacologia , Mialgia/tratamento farmacológico , Receptores Opioides mu/efeitos dos fármacos , Gânglio Trigeminal/efeitos dos fármacos , Dor Aguda/metabolismo , Dor Aguda/fisiopatologia , Animais , Modelos Animais de Doenças , Dor Facial/metabolismo , Dor Facial/fisiopatologia , Gânglios Espinais/metabolismo , Gânglios Espinais/fisiopatologia , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Mialgia/metabolismo , Mialgia/fisiopatologia , Ratos Wistar , Receptores Opioides mu/metabolismo , Gânglio Trigeminal/metabolismo , Gânglio Trigeminal/fisiopatologia
11.
Bioorg Med Chem Lett ; 28(3): 446-451, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29274816

RESUMO

Abuse of the common anti-diarrheal loperamide is associated with QT interval prolongation as well as development of the potentially fatal arrhythmia torsades de pointes. The mechanism underlying this cardiotoxicity is high affinity inhibition of the human ether-a-go-go-related gene (hERG) cardiac K+ channel. N-Desmethyl loperamide is the major metabolite of loperamide and is a close structural relative of the parent molecule. To date no information is available regarding the affinity of N-desmethyl loperamide for human cardiac ion channels. The effects of N-desmethyl loperamide on various cloned human cardiac ion channels including hERG, KvLQT1/mink and Nav1.5 were studied and compared to that of the parent. N-Desmethyl loperamide was a much weaker (7.5-fold) inhibitor of hERG compared to loperamide. However, given the higher plasma levels of the metabolite relative to the parent, it is likely that N-desmethyl loperamide can contribute, at least secondarily, to the cardiotoxicity observed with loperamide abuse. We used the recently solved cryo-EM structure of the hERG channel together with previously published inhibitors, to understand the basis of the interactions as well as the difference that a single methyl plays in the hERG channel blocking affinities of these two compounds.


Assuntos
Canal de Potássio ERG1/antagonistas & inibidores , Loperamida/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Relação Dose-Resposta a Droga , Canal de Potássio ERG1/metabolismo , Humanos , Loperamida/análogos & derivados , Loperamida/química , Modelos Moleculares , Estrutura Molecular , Bloqueadores dos Canais de Potássio/síntese química , Bloqueadores dos Canais de Potássio/química , Relação Estrutura-Atividade
12.
Ann Noninvasive Electrocardiol ; 23(2): e12505, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29125226

RESUMO

Loperamide is a popular antidiarrheal medication that has been used for many years. It is currently gaining more attention among healthcare professionals due to its increasing potential for side effects. At present, it is considered safe enough to be sold over the counter. In contrast with other opioid agonists, loperamide is a peripherally acting µ-receptor agonist exerting its effects mainly on the myenteric plexus of the gastrointestinal longitudinal muscle layer. It decreases peristalsis and fluid secretion resulting in longer gastrointestinal transit time. The bioavailability of the drug is extremely low. Moreover, it is actively excluded from the central nervous system; hence, it lacks the central effects of euphoria and analgesia at the recommended dosages. Loperamide abuse has been steadily increasing in the United States. Abusers typically ingest high doses in desire to achieve a satisfactory central nervous system drug penetration. This has made it a potential over the counter substitute for self-treating opioid withdrawal symptoms and achieving euphoric effects.


Assuntos
Antidiarreicos/efeitos adversos , Cardiotoxicidade/etiologia , Loperamida/toxicidade , Segurança do Paciente , Antidiarreicos/uso terapêutico , Cardiotoxicidade/fisiopatologia , Diarreia/tratamento farmacológico , Diarreia/fisiopatologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Humanos , Loperamida/farmacologia , Loperamida/uso terapêutico , Masculino , Medição de Risco
13.
J Food Sci ; 83(1): 205-211, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29165814

RESUMO

This study was conducted to compare the effects of juice and seeds on gastric emptying, small-bowel motility and intestinal ion transport. Separate groups of rats were randomized to receive NaCl, increasing doses of juice (5, 10, and 20 mL/kg, b.w.) or seeds aqueous extract (100, 200, and 400 mg/kg, b.w.). Simultaneously, two other groups were received, the reference drugs; clonidine (1 mg/kg) and yohimbine (2 mg/kg). The charcoal meal was used as a suspension for gastrointestinal motility test. The purgative action of juice was confirmed using the loperamide (5 mg/kg, p.o.) induced constipation. To evaluate the antisecretory effect, we were used as a hypersecretion agent, the castor oil at the dose of 5 mL/kg. Compared to the control and standard groups, we were showed that the prickly pear has an opposite effect on small-bowel motility and gastric emptying. Indeed, the juice at various doses has a laxative effect of gastrointestinal transit in healthy and constipated-rats. However, the aqueous extract of the seeds leads to a reduction of motility in normal rats which gives it a remarkable antidiarrhoeal activity, a notable intestinal fluid accumulation decline and electrolyte concentrations reestablishment. Moreover, orally juice administered at different doses accelerated the stomach emptying time in contrast to the seeds aqueous extract. More importantly, a significant variation in the phytochemical constituents levels between juice and seeds was found. These findings confirm the reverse therapeutic effects of this fruit in the treatment of digestive disturbances such as difficulty stool evacuation and massive intestinal secretion, likewise, the gastric emptying process perturbation.


Assuntos
Esvaziamento Gástrico/efeitos dos fármacos , Motilidade Gastrointestinal/efeitos dos fármacos , Opuntia/química , Extratos Vegetais/farmacologia , Sementes/química , Animais , Antidiarreicos/farmacologia , Constipação Intestinal/tratamento farmacológico , Diarreia/tratamento farmacológico , Relação Dose-Resposta a Droga , Frutas/química , Sucos de Frutas e Vegetais/análise , Loperamida/farmacologia , Masculino , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Fitoterapia , Ratos , Ratos Wistar
14.
Biol Pharm Bull ; 40(10): 1654-1660, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28966237

RESUMO

OTC drugs have an important role in self-medication. However, the pharmacokinetic properties of some OTC drugs have not been fully investigated and reports concerning their drug interactions are insufficient. Several gastrointestinal drugs are available as OTC drugs. Because of their pharmacological properties, these drugs are often used concomitantly with other drugs. Therefore, it is important to predict the possible drug interactions among these drugs. In the current study, we investigated the inhibitory effects of five gastrointestinal drugs, namely loperamide, oxethazaine, papaverine, pirenzepine, and trimebutine, on CYP activities in human liver microsomes. Furthermore, we calculated the ratio of the intrinsic clearance of each CYP substrate in the presence or absence of the gastrointestinal drugs. The possibility of drug interactions in vivo was predicted by cut-off criteria. CYP3A4 activity was markedly inhibited by trimebutine, papaverine, and oxethazaine. Their inhibitory properties were competitive and the Ki values were 6.56, 12.8, and 3.08 µM, respectively. Alternative R values of CYP3A4 exceeded the cut-off level. These results suggested that drug interactions mediated by CYP3A4 may occur during treatment with these gastrointestinal drugs, necessitating the confirmation of the clinical significance of these drug interactions to prevent unexpected adverse effects.


Assuntos
Inibidores das Enzimas do Citocromo P-450/farmacologia , Fármacos Gastrointestinais/farmacologia , Microssomos Hepáticos/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/metabolismo , Interações Medicamentosas , Etanolaminas/farmacologia , Humanos , Loperamida/farmacologia , Microssomos Hepáticos/enzimologia , Medicamentos sem Prescrição/farmacologia , Papaverina/farmacologia , Pirenzepina/farmacologia , Trimebutina/farmacologia
15.
J Basic Clin Physiol Pharmacol ; 28(5): 483-492, 2017 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-28771432

RESUMO

BACKGROUND: The objective of the study was to evaluate the antidiarrheal and antinociceptive activities of ethanol extract and its chloroform and pet ether fraction of Phrynium imbricatum (Roxb.) leaves in mice. METHODS: In the present study, the dried leaves of P. imbricatum were subjected to extraction with ethanol, and then it was fractioned by chloroform and pet ether solvent. Antidiarrheal effects were tested by using castor oil-induced diarrhea, castor oil-induced enteropooling, and gastrointestinal transit test. Antinociceptive activity was evaluated by using the acetic acid-induced writhing test and formalin-induced paw licking test. RESULTS: The standard drug loperamide (5 mg/kg) showed significant (p<0.001) inhibitory activity against castor oil-induced diarrhea, in which all the examined treatments decreased the frequency of defecation and were found to possess an anti-castor oil-induced enteropooling effect in mice by reducing both weight and volume of intestinal content significantly, and reducing the propulsive movement in castor oil-induced gastrointestinal transit using charcoal meal in mice. The results showed that the ethanol extract of P. imbricatum leaves has significant dose-dependent antinociceptive activity, and among its two different fractions, the pet ether fraction significantly inhibited the abdominal writhing induced by acetic acid and the licking times in formalin test at both phases. CONCLUSIONS: These findings suggest that the plant may be a potential source for the development of a new antinociceptive drug and slightly suitable for diarrhea, as it exhibited lower activity. Our observations resemble previously published data on P. imbricatum leaves.


Assuntos
Analgésicos/farmacologia , Antidiarreicos/farmacologia , Clorofórmio/química , Etanol/química , Marantaceae/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Animais , Óleo de Rícino/química , Diarreia/induzido quimicamente , Diarreia/tratamento farmacológico , Feminino , Loperamida/farmacologia , Camundongos
16.
Artigo em Inglês | MEDLINE | ID: mdl-28506204

RESUMO

BACKGROUND: Loperamide is an anti-diarrheal drug prescribed for non-infectious diarrhea. The drug is an opioid receptor agonist, blocker of voltage-dependent calcium channel (Cav) and calmodulin (CaM) inhibitor on human cells. Loperamide has been reported to exert anti-amoebic effects against pathogenic strains of Acanthamoeba castellanii. OBJECTIVES: The precise mode of antibiotic action, cellular target homology with human counterparts and the pattern of cell death induced by loperamide in Acanthamoeba castellanii remain to be established. Additionally, we attempt to establish the presence a primitive Cav in Acanthamoeba castellanii. METHODS: Bioinformatics, 3D structural modelling, ligand binding predictions and apoptotic/ amoebicidal assays were used in this study to answer the above queries. Amino acid sequences and structural models were compared between human and A. castellanii proteins that are involved in the regulation of calcium (Ca+2) homeostasis. RESULTS: Our results show that A. castellanii expresses similar, to near identical types of primitive calcium channels Cav Ac and CaM that are well known targets of loperamide in humans. The growth assays showed anti-amoebic effects of loperamide at different doses, both alone and in combinations with other Ca+2- CaM inhibitors. The synergistic actions of loperamide with haloperidol showed to be more amoebicidal than when either of them used alone. Imaging with Annexin V, Acridine orange and Propidium iodide showed apoptosis in A. castellanii at a dose of 100 µg/ml and necrosis at higher doses of 250 µg/ml. CONCLUSION: Though, Acanthamoeba does not express a homolog of the human mu-opioid receptor, but does shows evidence of the homologs for other known human targets of loperamide that are involved in Ca+2 uptake and Ca+2 signal transduction pathways. This suggests optimization of similar drug interactions with these targets may be useful in developing new approaches to control the growth of this parasite and possibly the diseases caused by it.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Antibacterianos/farmacologia , Diarreia/tratamento farmacológico , Loperamida/farmacologia , Proteínas de Protozoários/química , Acanthamoeba castellanii/química , Acanthamoeba castellanii/metabolismo , Acanthamoeba castellanii/patogenicidade , Sequência de Aminoácidos , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/química , Calmodulina/antagonistas & inibidores , Calmodulina/química , Biologia Computacional/métodos , Diarreia/parasitologia , Humanos , Ligantes , Modelos Moleculares , Terapia de Alvo Molecular/métodos , Ligação Proteica/efeitos dos fármacos , Proteínas de Protozoários/metabolismo , Receptores Opioides/agonistas , Receptores Opioides/química , Transdução de Sinais/efeitos dos fármacos , Homologia Estrutural de Proteína , Trofozoítos/efeitos dos fármacos
17.
Zebrafish ; 14(4): 322-330, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28488933

RESUMO

The objective of this study was to evaluate the permeability of small molecules into the brain via the blood-brain barrier in zebrafish and to investigate the possibility of using this animal model as a screening tool during the early stages of drug discovery. Fifteen compounds were used to understand the permeation into the brain in zebrafish and mice. The ratio of brain-to-plasma concentration was compared between the two animal models. The partition coefficient (Kp,brain), estimated using the concentration ratio at designated times (0.167, 0.25, 0.5, or 2 h) after oral administrations (per os, p.o), ranged from 0.099 to 5.68 in zebrafish and from 0.080 to 11.8 in mice. A correlation was observed between the Kp,brain values obtained from the zebrafish and mice, suggesting that zebrafish can be used to estimate Kp,brain to predict drug penetration in humans. Furthermore, in vivo transport experiments to understand the permeability glycoprotein (P-gp) transporter-mediated behavior of loperamide (LPM) in zebrafish were performed. The zebrafish, Kp,brain,30min of LPM was determined to be 0.099 ± 0.069 after dosing with LPM alone, which increased to 0.180 ± 0.115 after dosing with LPM and tariquidar (TRQ, an inhibitor of P-gp). In mouse, the Kp,brain,30min of LPM was determined to be 0.080 ± 0.004 after dosing with LPM alone and 0.237 ± 0.013 after dosing with LPM and TRQ. These findings indicate that the zebrafish could be used as an effective screening tool during the discovery stages of new drugs to estimate their distribution in the brain.


Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Ensaios de Triagem em Larga Escala/métodos , Loperamida/farmacologia , Modelos Animais , Quinolinas/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Animais , Antidiarreicos/farmacologia , Transporte Biológico/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Peixe-Zebra
18.
Eur J Pharmacol ; 806: 25-31, 2017 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-28410751

RESUMO

Chronic constipation is a highly common functional gastrointestinal disorder that adversely affects patient quality of life. At present, limited therapeutic options are available for the treatment of chronic constipation, which indicates the need for new therapeutic agents. Herein, we report the potential of mizagliflozin, a novel selective sodium glucose co-transporter 1 (SGLT1) inhibitor, for the amelioration of chronic constipation. Mizagliflozin's inhibitory activity against SGLTs was evaluated by an in vitro assay of cells transiently expressing SGLTs. The safety profile of an initial single dose (2-160mg, orally) and multiple doses (2-20mg, orally, once daily immediately prior to breakfast on Days 1 and 13, and three times daily immediately prior to every meal on Days 3-12) of mizagliflozin was determined by performing a phase I study in healthy male subjects. In addition, the effect of mizagliflozin and lubiprostone on fecal wet weight was compared using a dog model of loperamide-induced constipation and rat model of low-fiber-diet-induced constipation. Mizagliflozin potently inhibited human SGLT1 in a highly selective manner. The results of the phase I study showed mizagliflozin increased stool frequency and loosened stool consistency; these effects increased progressively with an increase in the dosage and the number of doses of mizagliflozin. In addition, the oral administration of mizagliflozin increased fecal wet weight in a dog model of loperamide-induced constipation and a rat model of low-fiber-diet-induced constipation, similar to lubiprostone. These results suggest the potential use of a novel selective SGLT1 inhibitor, mizagliflozin, for the amelioration of chronic constipation.


Assuntos
Amidas/farmacologia , Constipação Intestinal/tratamento farmacológico , Glucosídeos/farmacologia , Pirazóis/farmacologia , Transportador 1 de Glucose-Sódio/antagonistas & inibidores , Amidas/uso terapêutico , Animais , Doença Crônica/tratamento farmacológico , Ensaios Clínicos Fase I como Assunto , Constipação Intestinal/induzido quimicamente , Fibras na Dieta/farmacologia , Cães , Relação Dose-Resposta a Droga , Glucosídeos/uso terapêutico , Humanos , Loperamida/farmacologia , Masculino , Pirazóis/uso terapêutico , Ratos
19.
Neuropharmacology ; 117: 282-291, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28216001

RESUMO

Previous studies demonstrated that Loperamide, originally known as an anti-diarrheal drug, is a promising analgesic agent primarily targeting mu-opioid receptors. However some evidences suggested that non-opioid mechanisms may be contributing to its analgesic effect. In the present study, Loperamide was identified as a Nav1.7 blocker in a pilot screen. In HEK293 cells expressing Nav1.7 sodium channels, Loperamide blocked the resting state of Nav1.7 channels (IC50 = 1.86 ± 0.11 µM) dose-dependently and reversibly. Loperamide produced a 10.4 mV of hyperpolarizing shift for the steady-state inactivation of Nav1.7 channels without apparent effect on the voltage-dependent activation. The drug displayed a mild use- and state-dependent inhibition on Nav1.7 channels, which was removed by the local anesthetic-insensitive construct Nav1.7-F1737A. Inhibition of Nav1.7 at resting state was not altered significantly by the F1737A mutation. Compared to its effects on Nav1.7, Loperamide exhibited higher potency on recombinant Nav1.8 channels in ND7/23 cells (IC50 = 0.60 ± 0.10 µM) and weaker potency on Nav1.9 channels (3.48 ± 0.33 µM). Notably more pronounced inhibition was observed in the native Nav1.8 channels (0.11 ± 0.08 µM) in DRG neurons. Once mu-opioid receptor was antagonized by Naloxone in DRG neurons, potency of Loperamide on Nav1.8 was identical to that of recombinant Nav1.8 channels. The inhibition on Nav channels may be the main mechanism of Loperamide for pain relief beyond mu-opioid receptor. In the meanwhile, the opioid receptor pathway may also influence the blocking effect of Loperamide on sodium channels, implying a cross-talk between sodium channels and opioid receptors in pain processing.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Hiperalgesia/tratamento farmacológico , Inflamação/tratamento farmacológico , Loperamida/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Animais , Células CHO , Cricetulus , Relação Dose-Resposta a Droga , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Células HEK293 , Humanos , Hiperalgesia/etiologia , Hiperalgesia/metabolismo , Inflamação/complicações , Inflamação/metabolismo , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Técnicas de Patch-Clamp , Ratos Sprague-Dawley , Receptores Opioides mu/genética , Receptores Opioides mu/metabolismo , Proteínas Recombinantes/metabolismo , Canais de Sódio/genética , Canais de Sódio/metabolismo
20.
Mol Pain ; 122016.
Artigo em Inglês | MEDLINE | ID: mdl-27927796

RESUMO

Neuropathic pain, a distressing and debilitating disorder, is still poorly managed in clinic. Opioids, like morphine, remain the mainstay of prescribed medications in the treatment of this disorder, but their analgesic effects are highly unsatisfactory in part due to nerve injury-induced reduction of opioid receptors in the first-order sensory neurons of dorsal root ganglia. G9a is a repressor of gene expression. We found that nerve injury-induced increases in G9a and its catalyzed repressive marker H3K9m2 are responsible for epigenetic silencing of Oprm1, Oprk1, and Oprd1 genes in the injured dorsal root ganglia. Blocking these increases rescued dorsal root ganglia Oprm1, Oprk1, and Oprd1 gene expression and morphine or loperamide analgesia and prevented the development of morphine or loperamide-induced analgesic tolerance under neuropathic pain conditions. Conversely, mimicking these increases reduced the expression of three opioid receptors and promoted the mu opioid receptor-gated release of primary afferent neurotransmitters. Mechanistically, nerve injury-induced increases in the binding activity of G9a and H3K9me2 to the Oprm1 gene were associated with the reduced binding of cyclic AMP response element binding protein to the Oprm1 gene. These findings suggest that G9a participates in the nerve injury-induced reduction of the Oprm1 gene likely through G9a-triggered blockage in the access of cyclic AMP response element binding protein to this gene.


Assuntos
Proteína de Ligação a CREB/metabolismo , Gânglios Espinais/patologia , Histona-Lisina N-Metiltransferase/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Receptores Opioides mu/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Proteína de Ligação a CREB/genética , Modelos Animais de Doenças , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Lateralidade Funcional , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Histona-Lisina N-Metiltransferase/genética , Loperamida/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Entorpecentes/farmacologia , Entorpecentes/uso terapêutico , Ratos Sprague-Dawley , Receptores Opioides/genética , Receptores Opioides/metabolismo , Receptores Opioides delta/genética , Receptores Opioides delta/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos
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