Emerging drugs for the treatment of bladder storage dysfunction.

INTRODUCTION: Current drug treatment of lower urinary tract disorders, for example, overactive bladder syndrome and lower urinary tract symptoms associated with benign prostatic hyperplasia, is moderately effective, has a low treatment persistence and some short- and long-term adverse events. Even if combination therapy with approved drugs may offer advantages in some patients, there is still a need for new agents. AREAS COVERED: New b3-adrenoceptor agonists, antimuscarinics, the naked Maxi-K channel gene, a novel 5HT/NA reuptake inhibitor and soluble guanylate cyclase activators are discussed. Focus is given to P2X3 receptor antagonists, small molecule blockers of TRP channels, the roles of cannabis on incontinence in patients with multiple sclerosis, and of drugs acting directly on CB1 and CB2 receptor or indirectly via endocannabinoids by inhibition of fatty acid aminohydrolase. EXPERT OPINION: New potential alternatives to currently used drugs/drug principles are emerging, but further clinical testing is required before they can be evaluated as therapeutic alternatives. It seems that for the near future individualized treatment with approved drugs and their combinations will be the prevailing therapeutic approach.

Supplemental treatment to atropine improves the efficacy to reverse nerve agent induced bronchoconstriction.

Exposure to highly toxic organophosphorus compounds causes inhibition of the enzyme acetylcholinesterase resulting in a cholinergic toxidrome and innervation of receptors in the neuromuscular junction may cause life-threatening respiratory effects. The involvement of several receptor systems was therefore examined for their impact on bronchoconstriction using an ex vivo rat precision-cut lung slice (PCLS) model. The ability to recover airways with therapeutics following nerve agent exposure was determined by quantitative analyses of muscle contraction. PCLS exposed to nicotine resulted in a dose-dependent bronchoconstriction. The neuromuscular nicotinic antagonist tubocurarine counteracted the nicotine-induced bronchoconstriction but not the ganglion blocker mecamylamine or the common muscarinic antagonist atropine. Correspondingly, atropine demonstrated a significant airway relaxation following ACh-exposure while tubocurarine did not. Atropine, the M3 muscarinic receptor antagonist 4-DAMP, tubocurarine, the ß2-adrenergic receptor agonist formoterol, the Na+-channel blocker tetrodotoxin and the K+ATP-channel opener cromakalim all significantly decreased airway contractions induced by electric field stimulation. Following VX-exposure, treatment with atropine and the Ca2+-channel blocker magnesium sulfate resulted in significant airway relaxation. Formoterol, cromakalim and magnesium sulfate administered in combinations with atropine demonstrated an additive effect. In conclusion, the present study demonstrated improved airway function following nerve agent exposure by adjunct treatment to the standard therapy of atropine.

Auditory mismatch responses are differentially sensitive to changes in muscarinic acetylcholine versus dopamine receptor function.

The auditory mismatch negativity (MMN) has been proposed as a biomarker of NMDA receptor (NMDAR) dysfunction in schizophrenia. Such dysfunction may be caused by aberrant interactions of different neuromodulators with NMDARs, which could explain clinical heterogeneity among patients. In two studies (N = 81 each), we used a double-blind placebo-controlled between-subject design to systematically test whether auditory mismatch responses under varying levels of environmental stability are sensitive to diminishing and enhancing cholinergic vs. dopaminergic function. We found a significant drug × mismatch interaction: while the muscarinic acetylcholine receptor antagonist biperiden delayed and topographically shifted mismatch responses, particularly during high stability, this effect could not be detected for amisulpride, a dopamine D2/D3 receptor antagonist. Neither galantamine nor levodopa, which elevate acetylcholine and dopamine levels, respectively, exerted significant effects on MMN. This differential MMN sensitivity to muscarinic versus dopaminergic receptor function may prove useful for developing tests that predict individual treatment responses in schizophrenia.

Transcutaneous electrical nerve stimulation and solifenacin succinate versus solifenacin succinate alone for treatment of overactive bladder syndrome: A double-blind randomized controlled study.

OBJECTIVE: We evaluated a combination of transcutaneous electrical nerve stimulation (TENS) and solifenacin succinate versus solifenacin alone in the treatment of overactive bladder (OAB). METHODS: Ninety-seven female outpatients with OAB were screened for this double-blind randomized controlled study. Eighty-six patients who met our inclusion criteria were divided randomly into two groups. In group A (43 patients), patients received oral solifenacin and "fake" TENS on the foot; in group B (43 patients), patients received oral solifenacin and effective TENS on the foot. Improvements in OAB symptoms were assessed by Overactive Bladder Symptom Score (OABSS), Overactive Bladder Questionnaire (OAB-q), voiding diaries and urodynamic tests. 70 of 86 patients (36 in group A, 34 in group B) completed the 2 months of treatment and 3 months of follow-up. RESULTS: Statistically, the maximum bladder volume and OAB symptoms of both groups improved significantly after treatment. The improvement in group B was significantly better than that in group A, as indicated by the maximum bladder volume, OAB-q score and voiding diary. Some mild adverse effects were observed, including dry mouth, stomach upset, constipation, muscle pain and local paresthesia. CONCLUSION: The combination of TENS and solifenacin was more effective in improving OAB symptoms than solifenacin alone.

Efficacy of atropine and scopolamine on airway contractions following exposure to the nerve agent VX.

Nerve agents are highly toxic organophosphorus compounds that inhibit acetylcholinesterase resulting in rapid accumulation of the neurotransmitter acetylcholine (ACh) causing a cholinergic syndrome including respiratory failure. In the present study, respiratory responses and antimuscarinic treatment efficacy was evaluated ex vivo using rat precision-cut lung slices (PCLS) exposed to the nerve agent VX. The respiratory effects were evaluated either by adding exogenous ACh directly to the culture medium or by applying electric-field stimulation (EFS) to the PCLS to achieve a release of endogenous ACh from neurons in the lung tissue. The airway contraction induced by both methods was enhanced by VX and resulted in lingering airway recovery, in particular when airways were exposed to a high VX-dose. Both contractions induced by EFS and exogenously added ACh were significantly reduced by administration of the antimuscarinic drugs atropine or scopolamine. Two additions of atropine or scopolamine after maximal ACh-induced airway response was demonstrated effective to reverse the contraction. By adding consecutive doubled doses of antimuscarinics, high efficiency to reduce the cholinergic airway response was observed. However, the airways were not completely recovered by atropine or scopolamine, indicating that non-muscarinic mechanisms were involved in the smooth muscle contractions. In conclusion, it was demonstrated that antimuscarinic treatment reversed airway contraction induced by VX but supplemental pharmacological interventions are needed to fully recover the airways. Further studies should therefore clarify the mechanisms of physiological responses in lung tissue following nerve agent exposures to improve the medical management of poisoned individuals.

Aster tataricus alleviates constipation by antagonizing the binding of acetylcholine to muscarinic receptor and inhibiting Ca2+ influx.

BACKGROUND: The dried root and rhizome of Aster tataricus (RA), is a traditional Chinese medicine has been used for more than 2000 years with the function of antitussive, expectorant and antiasthmatic. Ancient books and modern pharmacological researches demonstrated that RA may have the function of moistening intestines and relieving constipation, but there was a lack of systematic evidence. The aim of this study was to comprehensively evaluate the efficacy and possible mechanisms of ethanol extract of Aster tataricus (ATE) in treating constipation from in vivo to in vitro. METHODS: In vivo, the ATE was studied in loperamide-induced constipation of mice. In vitro, different concentrations of ATE was tested separately or cumulatively on spontaneous and agonists-induced contractions of isolated rat duodenum strips. RESULTS: In vivo, at doses of 0.16, 0.8 g/mL, ATE showed significantly promotion of the small intestinal charcoal transit, decrease of the amount of remnant fecal, and increase of the content of fecal water in colon. In addition, ATE could effectively relieve colonic pathological damage caused by loperamide as well. In vitro, with the cumulative concentration increase of ATE from 0.8 to 6.4 mg/mL, it could significantly decrease the contraction caused by KCl or Ach, and gradually restore to near base tension value.Meanwhile, it could also partially but significantly inhibit the contractions induced by Ach and CaCl2 on rat duodenum in a concentration related manner. CONCLUSIONS: Taking all these findings together, it could be speculated that ATE may attenuate constipation mainly through antagonizing the binding of acetylcholine to muscarinic receptor, inhibiting Ca2+ influx and anti-inflammation.

Aster tataricus attenuates asthma efficiently by simultaneously inhibiting tracheal ring contraction and inflammation.

Asthma is an airway chronic inflammatory disease with significant morbidity, mortality and huge social economic burden. Previous research demonstrated that the root of Aster tataricus (RA) may have the potential to treat asthma, but the efficacy and mechanism were not clear. In this study, preliminary results in vitro showed that Fr-75 eluted from RA extract could not only completely inhibit the tracheal ring contraction raised by KCl in 20 min, but also effectively affect the tracheal ring contraction induced by KCl-, Ach- and His in a concentration-dependent manner (3.91-250 µg/mL). Further results on cells exhibited that Fr-75 could decrease the concentration of intracellular Ca2+ as well. These results revealed the underlying mechanism in vitro that the inhibition of tracheal ring contraction might be due to the decline of the intracellular Ca2+ concentration, which caused by suppressing calcium channel, antagonizing the muscarinic and histamine receptors. Also, results in vivo exhibited that Fr-75 could distinctly ease the symptoms of ovalbumin-sensitized mice, including relieving the pathological injury, increasing the latency to preconvulsive dyspnea and to enhanced pause, reducing the inflammatory cells, chemokines and cytokines in BALF and lung tissue. In general, it could be speculated that RA fraction may attenuate asthma through dilating the tracheal ring contraction and alleviating the lung inflammation simultaneously.

Acetylcholine acts on songbird premotor circuitry to invigorate vocal output.

Acetylcholine is well-understood to enhance cortical sensory responses and perceptual sensitivity in aroused or attentive states. Yet little is known about cholinergic influences on motor cortical regions. Here we use the quantifiable nature of birdsong to investigate how acetylcholine modulates the cortical (pallial) premotor nucleus HVC and shapes vocal output. We found that dialyzing the cholinergic agonist carbachol into HVC increased the pitch, amplitude, tempo and stereotypy of song, similar to the natural invigoration of song that occurs when males direct their songs to females. These carbachol-induced effects were associated with increased neural activity in HVC and occurred independently of basal ganglia circuitry. Moreover, we discovered that the normal invigoration of female-directed song was also accompanied by increased HVC activity and was attenuated by blocking muscarinic acetylcholine receptors. These results indicate that, analogous to its influence on sensory systems, acetylcholine can act directly on cortical premotor circuitry to adaptively shape behavior.

Emerging muscarinic receptor antagonists for the treatment of asthma.

INTRODUCTION: The increased acetylcholine signaling in asthma pathophysiology offers the rationale for the use of LAMAs in the treatment of asthmatic patients. Tiotropium is still the only LAMA approved for use in asthma but there is a real interest in developing novel LAMAs for the treatment of asthma, or at least to extend this indication to other LAMAs already on the market. AREAS COVERED: We examined and discussed trials and research that have studied or are evaluating the role of LAMAs already on the market in asthma and possible novel muscarinic acetylcholine receptor antagonists. EXPERT OPINION: Glycopyrronium and umeclidinium will soon be included in the GINA strategy with the same current indications of tiotropium. It is likely that the choice of the LAMA will be influenced not so much by its pharmacological profile as by the type of triple therapy chosen. It is extremely difficult to identify a new LAMA that is more effective than tiotropium, but is it plausible that new technologies that will allow delivering the drug in a more targeted way and with a lower risk of adverse effects may represent the real progress in the use of LAMAs in asthma in the coming years.

Evaluating revefenacin as a therapeutic option for chronic obstructive pulmonary disease.

INTRODUCTION: In chronic obstructive pulmonary disease (COPD), inhaled long-acting antimuscarinic agents (LAMA) are effective maintenance therapies used across all severity stages of the disease. Most of them are administered via dry powder inhalers, but these devices require a potent inspiratory flow which cannot be effectively achieved by patients with advanced disease. In such patients, inhaled therapy via nebulization might be an option. AREAS COVERED: Revefenacin is a LAMA that was specifically formulated for once daily nebulization and which was authorized by the FDA as a maintenance therapy for COPD. In phase II and III clinical studies discussed in this review, revefenacin demonstrated its rapid onset of action and sustained effect on lung function on both a short- and long-term basis. EXPERT OPINION: Nebulized revefenacin with once daily use does not require any particular effort of administration and hence can be used by patients with severe airways obstruction or by those having milder cognitive deficits. Further studies are needed, however, to better document the long-term cardiovascular safety and its ability to reduce the exacerbation rate.

Muscarinic-Dependent miR-182 and QR2 Expression Regulation in the Anterior Insula Enables Novel Taste Learning.

In a similar manner to other learning paradigms, intact muscarinic acetylcholine receptor (mAChR) neurotransmission or protein synthesis regulation in the anterior insular cortex (aIC) is necessary for appetitive taste learning. Here we describe a parallel local molecular pathway, where GABAA receptor control of mAChR activation causes upregulation of miRNA-182 and quinone reductase 2 (QR2) mRNA destabilization in the rodent aIC. Damage to long-term memory by prevention of this process, with the use of mAChR antagonist scopolamine before novel taste learning, can be rescued by local QR2 inhibition, demonstrating that QR2 acts downstream of local muscarinic activation. Furthermore, we prove for the first time the presence of endogenous QR2 cofactors in the brain, establishing QR2 as a functional reductase there. In turn, we show that QR2 activity causes the generation of reactive oxygen species, leading to modulation in Kv2.1 redox state. QR2 expression reduction therefore is a previously unaccounted mode of mAChR-mediated inflammation reduction, and thus adds QR2 to the cadre of redox modulators in the brain. The concomitant reduction in QR2 activity during memory consolidation suggests a complementary mechanism to the well established molecular processes of this phase, by which the cortex gleans important information from general sensory stimuli. This places QR2 as a promising new target to tackle neurodegenerative inflammation and the associated impediment of novel memory formation in diseases such as Alzheimer's disease.

Aclidinium bromide and formoterol fumarate for the maintenance treatment of chronic obstructive pulmonary disease.

Introduction: Treatment options for COPD have evolved rapidly in the last decade and inhaled bronchodilators have largely supplanted the use of oral bronchodilators because of their increased efficacy and excellent safety with topical delivery to the lung. Recently added to the therapeutic armamentarium are fixed-dose combinations (FDC) of two long acting bronchodilators. LAMAs (long acting muscarinic antagonists) and LABAs (long acting beta agonists) are the main classes available and use different pathways to effectively produce bronchial smooth muscle relaxation.Areas covered: The most recent inhaled FDC LAMA/LABA to come to market is Aclidinium Bromide and Formoterol Fumarate. We searched databases of PubMed, Cochrane Library, and manufacturers' websites and retrieved all the randomized-controlled trials (RCTs) conducted with these drugs up to September 2019.Expert opinion: It is likely that FDCs will become the core of our COPD pharmacotherapy for all but the mildest COPD patients. These individual drugs have excellent efficacy and safety records for the maintenance treatment of COPD. Studies have demonstrated that twice daily treatment with aclidinium/formoterol resulted in significant improvement in lung function and an improved exercise tolerance when compared to placebo. Adverse effects are within the range of what is seen with other LAMA/LABA combinations.

Current evidence for COPD management with dual long-acting muscarinic antagonist/long-acting ß2-agonist bronchodilators.

Long-acting inhaled bronchodilator medications are recommended as initial maintenance therapy for many patients with COPD. These medications include long-acting muscarinic antagonists (LAMA) and long-acting ß2-agonists (LABA). Combinations of long-acting bronchodilator agents (LAMA/LABA) and inhaled corticosteroids combined with LABA (ICS/LABA) are also used as initial or follow-up therapy in patients with more severe symptoms or at risk of COPD exacerbations. This review summarizes the position of LAMA/LABA combinations in treatment recommendations, and the evidence supporting their placement relative to LAMA monotherapy and ICS/LABA combination therapy, as well as differences within the LAMA/LABA class. Most studies show that LAMA/LABA treatment leads to greater improvements in lung function and symptoms than LAMA monotherapy or ICS/LABA treatment. There are fewer studies comparing the impact of different medication classes on patients' risk of exacerbations; however, the available evidence suggests that LAMA/LABA treatment and LAMA monotherapy lead to a similar reduction in exacerbation risk, while the effect of LAMA/LABA compared with ICS/LABA remains unclear. The incidence of adverse events is similar with LAMA/LABA and LAMA alone. There is a lower risk of pneumonia with LAMA/LABA compared with ICS/LABA. This evidence supports the use of LAMA/LABA combinations as an initial maintenance therapy option for symptomatic patients with low exacerbation risk and severe breathlessness or patients with severe symptoms who are at risk of exacerbations, and as follow-up treatment in patients with uncontrolled symptoms or exacerbations on bronchodilator monotherapy.

The Relaxant Effect of Plantago Major on Rat Tracheal Smooth Muscles and Its Possible Mechanisms.

This study was conducted to evaluate the possible mechanisms of the relaxant effects of hydroalcoholic extract of Plantago major (P. major) on tracheal smooth muscle (TSM) in rats. The effects of cumulative concentrations of P. major (5, 10, 20 and 40 mg/mL) and theophylline (0.2, 0.4, 0.6 and 0.8 mM) were evaluated on pre-contracted TSM with 10 µΜ methacholine or 60 mM KCl. To determine the possible mechanisms, the relaxant effect of the plant was also examined on incubated TSM with atropine, indomethacin, chlorpheniramine, glibenclamide, diltiazem, papaverine, and propranolol. The results indicated concentration-dependent relaxant effects for P. major in non-incubated TSM contracted by methacholine or KCl. There was no statistically significant difference in the relaxant effects of P. major between non-incubated and incubated tissues with indomethacin, papaverine, and propranolol. However, the relaxant effects of P. major in incubated tissues with atropine (p<0.01 to p<0.001), chlorpheniramine (p<0.05 to p<0.001), glibenclamide (p<0.05), or diltiazem (p<0.01) were significantly lower than non-incubated TSM. P. major indicated relatively potent relaxant effects which were lower than those of theophylline. Muscarinic and histamine (H1) receptors inhibition, as well as calcium channel blocking and potassium channel opening effects are suggested to contribute to the TSM relaxant effect of the plant.

Blood pressure lowering effects of Ranunculus scleratus Linn. in normal and fructose induced hypertensive rats and estimation of underlying mechanisms.

Ranunculus scleratus Linn. is used in folk medicine to treat hypertension. This study was aimed at providing validation to its traditional use and to explore underlying mechanisms of action. Effects of hydro-ethanolic crude extract of the plant and its fractions on blood pressure was evaluated using direct surgical method in normotensive and in fructose induced hypertensive rats. Various doses of crude extract, RSC, (5, 10, 20, 30mg/kg) and all fractions (3, 5, 10, 20mg/kg) were studied. Results suggested that aqueous fraction of R. scleratus (RSA) produced most pronounced effects at 10mg/kg in normotensive and at 20mg/kg in hypertensive animals. Underlying mechanisms, using various pharmacological antagonists were also elucidated. Results suggested the involvement of muscarinic receptor, angiotensin converting enzyme (ACE) inhibition, ganglionic block and nitric oxide (NO) release in presenting hypotensive response.

Beclomethasone dipropionate, formoterol fumarate and glycopyrronium bromide: Synergy of triple combination therapy on human airway smooth muscle ex vivo.

BACKGROUND AND PURPOSE: Combining inhaled corticosteroids (ICSs), long-acting ß2 -adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) is recommended to treat severe forms of asthma and chronic obstructive pulmonary disease (COPD). Clinical benefits have been demonstrated for ICS/LABA/LAMA combinations. This study characterized the interaction between the ICS beclomethasone dipropionate, the LABA formoterol fumarate and the LAMA glycopyrronium bromide in human airways. EXPERIMENTAL APPROACH: Human passively sensitized airways and bronchi from COPD donors were stimulated with histamine or carbachol. Tissues were incubated overnight with beclomethasone and then treated with formoterol and glycopyrronium, alone or in triple combination. The interaction was assessed by using Bliss Independence and Unified Theory theorems. KEY RESULTS: Beclomethasone/formoterol/glycopyrronium combination synergistically relaxed medium bronchi and small airways. Beclomethasone/formoterol/glycopyrronium combination at 100:6:12.5 combination ratio was a balanced drug mixture leading to very strong synergistic effect on relaxation of medium bronchi (Combination Index: from 0.042 to 0.96) and middle to very strong synergy in small airways (Combination Index: from 0.018 to 0.310). The synergy was related with the activation of intracellular glucocorticoid receptors and Gsα subunit G-protein of ß2 -adrenoceptors, leading to the modulation of cyclic AMP-dependent PKA pathway. CONCLUSION: Triple beclomethasone/formoterol/glycopyrronium combination induces synergistic bronchorelaxant effect in medium and small human airways, at least in ex vivo experiments. Further research is needed to confirm these findings in clinical studies in patients with asthma or COPD.

Strain differences in muscarinic cholinergic receptor antagonism of fat intake and acquisition and expression of fat-conditioned flavor preferences in male BALB/c, C57BL/6 and SWR mice.

Murine strain differences occur for both intakes of and preferences for sugars and fats. Previous studies demonstrated that the muscarinic cholinergic receptor antagonist, scopolamine (SCOP) more potently reduced sucrose and saccharin intakes in inbred C57BL/6 and BALB/c than SWR mice, sucrose-conditioned flavor preferences (CFP) expression in BALB/c, but not C57BL/6 or SWR mice, and sucrose-CFP acquisition in BALB/c relative to SWR and C57BL/6 mice. Although fat intake and fat-CFP are observed in all three strains, strain-specific effects were previously observed following dopamine D1, opiate and NMDA receptor antagonism of sweet and fat intake and CFP. The present study investigated whether muscarinic receptor antagonism differentially affected fat (Intralipid) intake and preferences in these strains by examining whether SCOP altered fat (Intralipid) intake and fat-CFP expression and acquisition in BALB/c, C57BL/6 and SWR mice. SCOP (0.1-10 mg/kg) significantly reduced Intralipid (5%) intake in all three strains across 2 h. In fat-CFP expression experiments, food-restricted mice consumed one flavored (conditioned stimulus (CS)+, 5 sessions) Intralipid (5%) solution and a differently-flavored (CS-, 5 sessions) Intralipid (0.5%) solution. Two-bottle CS choice tests with the two flavors mixed in 0.5% Intralipid occurred following vehicle and two SCOP doses (1, 5 mg/kg). SCOP elicited small, but significant reductions in fat-CFP expression in BALB/c and C57BL/6, but not SWR mice. In fat-CFP acquisition experiments, separate groups of BALB/c, C57BL/6 and SWR mice were treated prior to the ten acquisition training sessions with vehicle or two SCOP (2.5, 5 mg/kg) doses followed by six two-bottle choice tests without injections. SCOP eliminated fat-CFP acquisition in all three strains. Thus, muscarinic receptor signaling mediates learning, and to a lesser degree maintenance of fat-CFP while maximally inhibiting fat intake in the three strains.

Efficacy and cardiovascular safety profile of dual bronchodilation therapy in chronic obstructive pulmonary disease: A bidimensional comparative analysis across fixed-dose combinations.

Despite several long-acting ß2-adrenoceptor agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations (FDCs) are currently approved for the treatment of chronic obstructive pulmonary disease (COPD), there are limited findings concerning the direct comparison across the different LABA/LAMA FDCs. The aim of this study was to compare the efficacy/safety profile of approved LABA/LAMA FDCs in COPD. A network meta-analysis was performed by linking the efficacy (forced expiratory volume in 1 s, St' George Respiratory Questionnaire, transitional dyspnea index) and safety (cardiovascular serious adverse events) outcomes resulting from randomized controlled trials that directly compared LABA/LAMA FDCs with placebo and/or each other. The Surface Under the Cumulative Ranking Curve Analysis (SUCRA) was performed for each single outcome (SUCRA: 1 = best, 0 = worst). The combined efficacy/safety profile was reported via the novel Improved Bidimensional SUCRA score (IBiS: the higher the value the better the treatment). Data obtained from 12,136 COPD patients (79.50% LABA/LAMA FDCs vs. placebo; 20.50% direct comparison between different LABA/LAMA FDCs) were extracted from 22 studies published between 2013 and 2019. The IBiS score showed the following rank of efficacy/safety profile: tiotropium/olodaterol 5/5 µg (area 66.83%) ¼ glycopyrronium/indacaterol 15.6/27.5 µg (area 40.43%)  >  umeclidinium/vilanterol 62.5/25 µg (area 30.48%)  ≈  aclidinium/formoterol 400/12 µg (area 28.44%)  >  glycopyrronium/indacaterol 50/110 µg (area 19.95%)  >  glycopyrronium/formoterol 14.4/9.6 µg (area 11.50%). Each available LABA/LAMA FDC has a specific efficacy/safety profile that needs to be considered for personalized therapy in COPD. Head-to-head studies aimed to assess the impact of different LABA/LAMA FDCs on the risk of COPD exacerbation are needed to further improve the information provided by this quantitative synthesis.

Rapid-acting antidepressants.

Conventional antidepressants (biogenic amine mechanisms) are not fully efficacious (e.g., symptoms remain after treatment, not all patients respond), produce effects only after weeks of daily dosing, and do not impact all disease symptoms. In contrast, a new class of antidepressants has been emerging since 2006 that has demonstrated rapid onset, large effect size, activity after only a single or few dose applications, and positive impact in treatment refractory patients and against some treatment-resistant symptoms (e.g., anhedonia). Rapid-acting antidepressant drug action has been demonstrated in controlled clinical studies for ketamine, a few other NMDA receptor antagonists, and scopolamine. Less clinical data are currently available for psychedelic drugs such as psilocybin, lysergic acid diethylamide, and ayahuasca. The mechanisms of action of rapid-acting antidepressants are not fully understood. However, a general triggering mechanism appears to involve the potentiation of AMPA receptor function. Although the durability of antidepressant effects of ketamine and scopolamine is limited, psychedelic drugs have been reported to produce effects for many months. The primary impediment to generating a medicine of this type for depressed patients is side effects and the lack of methods to ensure enduring antidepressant effects. Thus, further exploration of drug possibilities continues. Esketamine ((S)-ketamine) was recently FDA approved. Compounds currently in clinical development include the NMDA receptor antagonist (R)-ketamine, the NMDA receptor modulator, GLYX-13 (Rapastinel), and the AMPA receptor potentiator TAK-653. Additional pharmacological classes have produced effects in the preclinical laboratory to suggest their potential as rapid-acting agents. These include mGlu2/3 receptor antagonists, AMPA receptor potentiators, and negative allosteric modulators of GABAA(α5) receptors. In all cases, molecules exist that could be used to provide clinical proof of concept testing.

Elucidation of the possible mechanism of analgesic action of methanol stem bark extract of Uapaca togoensis pax in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Uapaca togoensis is a medicinal plant used traditionally in Africa for the treatment of rheumatism, epilepsy, cough, pneumonia, vomitting and fever. Previously, the analgesic activity of its methanol stem bark extract has been scientifically demonstrated. However, the mechanism responsible for this activity remains to be investigated. AIM OF THE STUDY: To elucidate the possible mechanism(s) through which the methanol stem bark extract of Uapaca togoensis (MEUT) exhibits analgesic activity in mice. MATERIALS AND METHODS: Analgesic activity of MEUT was evaluated using acetic acid-induced abdominal writhing test in mice at doses of 250, 500 and 1000 mg/kg orally. For the mechanistic studies, mice were pre-treated with Naloxone (2 mg/kg), Atropine (1 mg/kg), Yohimbine (1 mg/kg), Glibenclamide (10 mg/kg), Prazosin (1 mg/kg) and Yohimbine (1 mg/kg) 15 min prior to MEUT (1000 mg/kg) administration, then assessed using AAWT 1 h later. Data was analysed using One way Anova followed by Bonferroni post hoc test. RESULTS: The extract (at the doses of 250, 500 and 1000 mg/kg) and morphine (10 mg/kg) significantly (p < 0.05) decreased the number of abdominal writhes. Naloxone (opioid receptor antagonist), Atropine (muscarinic receptor antagonist) and Glibenclamide (ATP-sensitive K+ channel blocker) significantly (p < 0.05) reversed the analgesic effect of MEUT. On the other hand, Prazosin and Yohimbine (α1 and α2 receptor antagonists respectively) had no effect on the analgesic action of MEUT. CONCLUSION: The results obtained from this study suggests the possible involvement of opioidergic, cholinergic and sensitive potassium ATP channel pathways in the analgesic activity of the methanol stem bark extract of Uapaca togoensis.