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Background: The serotonin 4 receptor (5-HT 4 R) is a promising target for the treatment of depression. Highly selective 5-HT 4 R agonists, such as prucalopride, have antidepressant-like and procognitive effects in preclinical models, but their clinical effects are not yet established., Aims: To determine whether prucalopride (a 5-HT 4 R agonist and licensed treatment for constipation) is associated with reduced incidence of depression in individuals with no past history of mental illness, compared with anti-constipation agents with no effect on the central nervous system., Method: Using anonymised routinely collected data from a large-scale USA electronic health records network, we conducted an emulated target trial comparing depression incidence over 1 year in individuals without prior diagnoses of major mental illness, who initiated treatment with prucalopride versus two alternative anti-constipation agents that act by different mechanisms (linaclotide and lubiprostone). Cohorts were matched for 121 covariates capturing sociodemographic factors, and historical and/or concurrent comorbidities and medications. The primary outcome was a first diagnosis of major depressive disorder (ICD-10 code F32) within 1 year of the index date. Robustness of the results to changes in model and population specification was tested. Secondary outcomes included a first diagnosis of six other neuropsychiatric disorders., Results: Treatment with prucalopride was associated with significantly lower incidence of depression in the following year compared with linaclotide (hazard ratio 0.87, 95% CI 0.76-0.99; P = 0.038; n = 8572 in each matched cohort) and lubiprostone (hazard ratio 0.79, 95% CI 0.69-0.91; P < 0.001; n = 8281). Significantly lower risks of all mood disorders and psychosis were also observed. Results were similar across robustness analyses., Conclusions: These findings support preclinical data and suggest a role for 5-HT 4 R agonists as novel agents in the prevention of major depression. These findings should stimulate randomised controlled trials to confirm if these agents can serve as a novel class of antidepressant within a clinical setting.

Background: Felcisetrag (5-hydroxytryptamine-4 receptor [5-HT 4 ] agonist) is under investigation as prophylaxis or active treatment for accelerating resolution of gastrointestinal function post-surgery., Methods: Phase 2, randomized, placebo-controlled, parallel five-arm, double-blind, multicenter study (NCT03827655) in 209 adults undergoing open or laparoscopic-assisted bowel surgery. Patients received intravenous placebo, felcisetrag 0.1 mg/100 ​mL or 0.5 mg/100 ​mL pre-surgery only, or pre-surgery and daily post-surgery until return of gastrointestinal function or for up to 10 days., Primary Endpoint: time to recovery of gastrointestinal function., Results: Median time to recovery of gastrointestinal function was 2.6 days for both felcisetrag 0.5 ​mg daily and 0.5 ​mg pre-surgery versus 1.9 days for placebo (p ​> ​0.05). There were no notable differences in adverse events between treatment arms., Conclusions: Felcisetrag was well tolerated with no new safety concerns. However, no clinically meaningful difference in time to recovery of gastrointestinal function versus placebo was observed. Further investigation of the utility of 5-HT 4 agonists in complicated, open abdominal surgeries may be warranted., Competing Interests: Declaration of competing interest GB has received a research grant from Takeda and is an Editorial Board Member for Gut. SA has nothing to declare. ME has nothing to declare. GD was an employee of Takeda Development Center Americas, Inc. and received stock or stock options at the time of the study; they are currently an employee of Ironwood Pharmaceuticals, Inc. RG, PK, JT, PT, JW, and YZ are employees of Takeda Development Center Americas, Inc. and receive stock or stock options. PRW was an employee of Takeda Development Center Americas, Inc. and received stock or stock options at the time of the study; he is currently the founding principal at Second Brain Consulting, LLC, Philadelphia, PA, USA., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Prolonged postoperative ileus (PPOI) contributes to morbidity and prolonged hospitalization. Prucalopride, a selective 5-hydroxytryptamine receptor agonist, may enhance bowel motility. This review assesses whether the perioperative use of prucalopride compared to placebo is associated with accelerated return of bowel function post gastrointestinal (GI) surgery., Methods: OVID, CENTRAL, and EMBASE were searched as of January 2024 to identify randomized controlled trials (RCTs) comparing prucalopride and placebo for prevention of PPOI in adult patients undergoing GI surgery. The primary outcomes were time to stool, time to flatus, and time to oral tolerance. The secondary outcomes were incidence of PPOI, length of stay (LOS), postoperative complications, adverse events, and overall costs. The Cochrane risk of bias tool for randomized trials and the Grading of Recommendations, Assessment, Development, and Evaluations framework were used. An inverse variance random effects model was used., Results: From 174 citations, 3 RCTs with 139 patients in each treatment group were included. Patients underwent a variety of GI surgeries. Patients treated with prucalopride had a decreased time to stool (mean difference 36.82 hours, 95% CI 59.4 to 14.24 hours lower, I 2 = 62%, low certainty evidence). Other outcomes were not statistically significantly different (very low certainty evidence). Postoperative complications and adverse events could not be meta-analyzed due to heterogeneity; yet individual studies suggested no significant differences (very low certainty evidence)., Discussion: Current RCT evidence suggests that prucalopride may enhance postoperative return of bowel function. Larger RCTs assessing patient important outcomes and associated costs are needed before routine use of this agent., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: This real-world US-based claims study compared constipation-related symptoms and complications 6 months before and after prucalopride initiation in adults with chronic idiopathic constipation (CIC)., Methods: This observational, retrospective cohort analysis used the IBM MarketScan Commercial Claims and Encounters Database and the Medicare Supplemental Database (January 2015-June 2020). Prucalopride-treated patients (≥18 years old) who had ≥1 constipation-related International Classification of Diseases, Tenth Revision, Clinical Modification ( ICD-10-CM ) diagnosis code during the baseline or study period were included. The proportions of patients with constipation-related symptoms (abdominal pain, abdominal distension [gaseous], incomplete defecation, and nausea) and constipation-related complications (anal fissure and fistula, intestinal obstruction, rectal prolapse, hemorrhoids, perianal venous thrombosis, perianal/perirectal abscess, and rectal bleeding) were examined. Constipation-related symptoms and complications were identified using ICD-10-CM , ICD-10 - Procedure Coding System , or Current Procedural Terminology codes. Data were stratified by age (overall, 18-64 years, and ≥65 years)., Results: This study included 690 patients: The mean (SD) patient age was 48.0 (14.7) years, and 87.5% were women. The proportions of patients overall with constipation-related symptoms decreased 6 months after prucalopride initiation (abdominal pain [50.4% vs 33.3%, P < 0.001]; abdominal distension [gaseous] [23.9% vs 13.3%, P < 0.001]; and nausea [22.6% vs 17.7%, P < 0.01]; no improvements observed for incomplete defecation). Similarly, the proportions of patients overall with constipation-related complications decreased 6 months after prucalopride initiation (intestinal obstruction [4.9% vs 2.0%, P < 0.001]; hemorrhoids [10.7% vs 7.0%, P < 0.05]; and rectal bleeding [4.1% vs 1.7%, P < 0.05])., Discussion: This study suggests that prucalopride may be associated with improved constipation-related symptoms and complications 6 months after treatment initiation., (Copyright © 2024 Takeda Pharmaceuticals USA, Inc. Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Prokinetic agents, specifically 5-hydroxytryptamine type 4 (5-HT 4 ) receptor agonists, have been shown to provide relief in chronic idiopathic constipation (CIC). The first-generation 5-HT 4 agonists were initially withdrawn from use owing to associations with serious cardiovascular (CV) events. This review summarizes CV safety data for prucalopride, a high-affinity 5-HT 4 agonist approved in the United States in 2018 for adults with CIC. No significant effects of prucalopride on CV safety were observed in animal models or early-phase clinical studies, including a thorough QT study at therapeutic (2 mg) or supratherapeutic (10 mg) doses. Among 1,750 patients with CIC who received prucalopride (2-4 mg) in 5 phase 3 studies, no trends in CV adverse events, electrocardiogram parameters, or blood pressure were documented; ≤1.0%-2.0% of patients had prolonged QT interval corrected for heart rate (HR) using Fridericia formula after placebo or prucalopride treatment, and low HR occurred in ≤6.1% and ≤3.3% of these patients, respectively. In two 24-month observational studies among 2,468 patients, changes in electrocardiogram parameters over time were minor, except at occasional time points when significant changes from baseline were reported for HR or QT interval. In a real-world European CV safety study among 35,087 patients (prucalopride, 5,715; polyethylene glycol 3350 [PEG3350], 29,372), results were consistent for no evidence of increased risk of major adverse CV events among patients treated with prucalopride vs PEG3350 (incidence rate ratio = 0.64; 95% confidence interval 0.36-1.14). Studies to date have not raised concerns regarding the impact of prucalopride treatment on CV parameters., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Because of their importance in the regulation of gut functions, several therapeutic targets involving serotonin-related proteins have been developed or repurposed to treat motility disorders, including serotonin transporter inhibitors, tryptophan hydroxylase blockers, 5-HT3 antagonists, and 5-HT4 agonists. This chapter focuses on our discovery of 5-HT4 receptors in the epithelial cells of the colon and our efforts to evaluate the effects of stimulating these receptors. 5-HT4 receptors appear to be expressed by all epithelial cells in the mouse colon, based on expression of a reporter gene driven by the 5-HT4 receptor promoter. Application of 5-HT4 agonists to the mucosal surface causes serotonin release from enterochromaffin cells, mucus secretion from goblet cells, and chloride secretion from enterocytes. Luminal administration of 5-HT4 agonists speeds up colonic motility and suppresses distention-induced nociceptive responses. Luminal administration of 5-HT4 agonists also decreases the development of, and improves recovery from, experimental colitis. Recent studies determined that the prokinetic actions of minimally absorbable 5-HT4 agonists are just as effective as absorbable compounds. Collectively, these findings indicate that targeting epithelial receptors with non-absorbable 5-HT4 agonists could offer a safe and effective strategy for treating constipation and colitis., (© 2022. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Background: Postoperative ileus is common and is a major clinical problem. It has been widely studied in patients and in experimental models in laboratory animals. A wide variety of treatments have been tested to prevent or modify the course of this disorder., Purpose: This review draws together information on animal studies of ileus with studies on human patients. It summarizes some of the conceptual advances made in understanding the mechanisms that underlie paralytic ileus. The treatments that have been tested in human subjects (both pharmacological and non-pharmacological) and their efficacy are summarized and graded consistent with current clinical guidelines. The review is not intended to provide a comprehensive overview of ileus, but rather a general understanding of the major clinical problems associated with it, how animal models have been useful to elucidate key mechanisms and, finally, some perspectives from both scientists and clinicians as to how we may move forward with this debilitating yet common condition., (© 2020 John Wiley & Sons Ltd.)

Animal experimental studies suggest that 5-HT4 receptor activation holds promise as a novel target for the treatment of depression and cognitive impairment. 5-HT4 receptors are post-synaptic receptors that are located in striatal and limbic areas known to be involved in cognition and mood. Consistent with this, 5-HT4 receptor agonists produce rapid antidepressant effects in a number of animal models of depression, and pro-cognitive effects in tasks of learning and memory. These effects are accompanied by molecular changes, such as the increased expression of neuroplasticity-related proteins that are typical of clinically useful antidepressant drugs. Intriguingly, these antidepressant-like effects have a fast onset of their action, raising the possibility that 5-HT4 receptor agonists may be a particularly useful augmentation strategy in the early stages of SSRI treatment. Until recently, the translation of these effects to humans has been challenging. Here, we review the evidence from animal studies that the 5-HT4 receptor is a promising target for the treatment of depression and cognitive disorders, and outline a potential pathway for the efficient and cost-effective translation of these effects into humans and, ultimately, to the clinic.

Background: 5-HT 4 receptor (5-HT 4 R) agonists exert prokinetic actions in the GI tract, but non-selective actions and potential for stimulation of non-target 5-HT 4 Rs have limited their use. Since 5-HT 4 Rs are expressed in the colonic epithelium and their stimulation accelerates colonic propulsion in vitro, we tested whether luminally acting 5-HT 4 R agonists promote intestinal motility., Methods: Non-absorbed 5-HT 4 R agonists, based on prucalopride and naronapride, were assessed for potency at the 5-HT 4 R in vitro, and for tissue and serum distribution in vivo in mice. In vivo assessment of prokinetic potential included whole gut transit, colonic motility, fecal output, and fecal water content. Colonic motility was also studied ex vivo in mice treated in vivo. Immunofluorescence was used to evaluate receptor distribution in human intestinal mucosa., Key Results: Pharmacological screening demonstrated selectivity and potency of test agonists for 5-HT 4 R. Bioavailability studies showed negligible serum detection. Gavage of agonists caused faster whole gut transit and colonic motility, increased fecal output, and elevated fecal water content. Prokinetic actions were blocked by a 5-HT 4 R antagonist and were not detected in 5-HT 4 R knockout mice. Agonist administration promoted motility in models of constipation. Evaluation of motility patterns ex vivo revealed enhanced contractility in the middle and distal colon. Immunoreactivity for 5-HT 4 R is present in the epithelial layer of the human small and large intestines., Conclusions and Inferences: These findings demonstrated that stimulation of epithelial 5-HT 4 Rs can potentiate propulsive motility and support the concept that mucosal 5-HT 4 Rs could represent a safe and effective therapeutic target for the treatment of constipation., (© 2020 John Wiley & Sons Ltd.)

Background and Aim: Paralytic ileus is a common intestinal dysfunction in critically ill patients, which results in complications and poor hospital outcomes. There are still no established effective medications, except correcting the primary causes and prokinetics trial, which have limited efficacy and potential adverse events. This study aims to evaluate the efficacy of prucalopride on paralytic ileus in critically ill patients., Methods: A randomized, double-blind, placebo-controlled trial of five consecutive days treatment periods was conducted. Critically ill patients with paralytic ileus were included. The primary endpoint was the improvement of bowel dilatation on plain abdominal radiography. The secondary endpoint was the change of abdominal circumference., Results: Twenty patients were consecutively enrolled in the study. There was no significant difference in baseline characteristics of patients. The common causes of hospitalization were infection and respiratory problems. The maximum large bowel diameters dramatically decreased in prucalopride group and reached maximum point on the third day after intervention when compared with placebo (-2.1 [± 1.8] vs 0.3 [± 1.5] cm, P = 0.01). The maximum small bowel diameters were noticeably less decreased and were not significantly different when compared with placebo. The abdominal circumferences notably decreased and significantly diverged from placebo on the third day., Conclusions: Prucalopride was an effective enterokinetic agent to improve non-severe inflammatory/ischemic bowel conditions related paralytic ileus in critically ill patients. Its effect was predominant on large intestine but could not be well demonstrated on small bowel in this study. Future study or concomitant other prokinetics for upper gut motility should be further evaluated., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background: Gastroparesis, defined by delayed gastric emptying in the absence of mechanical outlet obstruction, is a frequent neuropathic complication of diabetes mellitus, and effective treatments are lacking. Prucalopride is a pan-gut prokinetic with selective agonist effects on serotonin 5-HT4 receptors in the gut. This study aimed to assess the effect of prucalopride 4 mg daily on Gastroparesis Cardinal Symptom Index (GCSI), meal-related symptom score (MRSS), and gastric emptying rate in diabetic or connective tissue disease (CTD)-related gastroparesis patients., Methods: This was a double-blind crossover trial of four-week treatment periods with prucalopride or placebo divided by two weeks of washout. GSCI, MRSS, gastric emptying scintigraphy, PAGI-SYM, and PAGI-QoL were assessed at baseline and the end of each treatment period. Daily bowel movement (BM) frequency and gastrointestinal symptoms were recorded in each period., Key Results: Fifteen gastroparesis patients (13 diabetic, 2 CTD) were enrolled. GCSI scores were lower than baseline but not different between treatment arms. MRSS scores over time or cumulative score were not significantly different between groups. Gastric emptying was more rapid in the prucalopride treatment period, with mean four-hour meal retention of 22 ± 6% in PRU period vs 40 ± 9% in the placebo period (P = 0.05). Weekly BM frequency was significantly higher in prucalopride than placebo periods (10.5 ± 1.8 vs 7.5 ± 0.8, P < 0.0001). Perception of weight loss was higher in patients on prucalopride. Analysis of diabetic gastroparesis (n = 13) population did not change the conclusions., Conclusion and Inference: Prucalopride at 4 mg accelerates gastric emptying and bowel movement frequency but does not appear to ameliorate gastroparesis or meal-related symptoms in this study., (© 2020 John Wiley & Sons Ltd.)

Objective: Post dural puncture headache (PDPH) is a common complication in patients following diagnostic or therapeutic lumbar puncture, procedures requiring epidural access, and spinal surgery. Epidural blood patch (EBP), the gold standard for the treatment of this pathology requires training not provided to emergency physicians. In addition, the presence of concomitant pathology and abnormal laboratory values are contraindications to perform EBP. In presence of these limitations, we sought for a non-interventional management of PDPH utilizing high-flow oxygen and pro-serotonin agents. We reviewed the mechanism of action of this therapy METHODS: To illustrate our proposal, we report a series of twelve consecutive patients with PDPH treated with high-flow oxygen therapy at 12 L/min via a non-rebreathing mask and intravenous metoclopramide., Results: All patients were treated with this conservative therapy, no adverse reactions were observed. After the intervention, the headache resolved without further indications for PDPH., Conclusion: Our series suggests that combining high-flow oxygen and pro-serotonin agents such metoclopramide in the ED might be a feasible option as effective as the invasive methods used in treating PDPH. This therapy appears to be efficient and to minimize risk, cost and side effects. It presents an easily accessible alternative that should be considered when PDPH is not a viable option., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Agonists of 5-hydroxytryptamine 4 receptor are potential agents for irritable bowel syndrome with predominant constipation (IBS-C). However, only tegaserod has been approved for a very limited population in the US., Aim: To evaluate the efficacy and safety of minesapride in patients with Rome IV defined IBS-C., Methods: A double-blind, placebo-controlled, dose-finding study was performed. Overall, 411 patients were randomised to receive minesapride at 10, 20 or 40 mg/d, or placebo for 12 weeks. The primary endpoint was Food and Drug Administration (FDA) composite endpoint (responder: a patient who reported an increase in one or more complete spontaneous bowel movements from baseline and improvement of ≥30% from baseline in weekly average of worst abdominal pain score, both in the same week for ≥6/12 weeks)., Results: The FDA composite responder rate was 13.6% (14/103) in the placebo group, 13.6% (14/103) in the 10 mg group, 19.2% (20/104) in the 20 mg group and 14.9% (15/101) in the 40 mg group, and no dose-response relationship was found. A greater percentage of minesapride 40 mg-treated patients than placebo-treated patients met both responder requirements for ≥9/12 weeks as the stricter composite evaluation (P < 0.05). Furthermore, minesapride 40 mg significantly increased SBM frequency compared with placebo (adjusted P < 0.001 at Week 12). The most common adverse event was mild diarrhoea., Conclusions: Minesapride was safe and well-tolerated. Although the primary endpoint was negative, minesapride 40 mg is likely to improve the stricter composite endpoint and SBM frequency. Japan Pharmaceutical Information Center Number: Japic CTI-163459., (© 2020 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

The Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling pathway plays central roles in cancer cell growth and survival. Drug repurposing strategies have provided a valuable approach for developing antitumor drugs. Zelnorm (tegaserod maleate) was originally designed as an agonist of 5-hydroxytryptamine 4 receptor (5-HT4R) and approved by the FDA for treating irritable bowel syndrome with constipation (IBS-C). Through the use of a high-throughput drug screening system, Zelnorm was identified as a JAK/STAT3 signaling inhibitor. Moreover, the inhibition of STAT3 phosphorylation by Zelnorm was independent of its original target 5-HT4R. Zelnorm could cause G1 cell cycle arrest, induce cell apoptosis and inhibit the growth of a variety of cancer cells. The present study identifies Zelnorm as a novel JAK/STAT3 signaling inhibitor and reveals a new clinical application of Zelnorm upon market reintroduction.

Introduction: Constipation is common in patients with Parkinson's disease (PD). Due to the considerable negative outcomes of constipation, significant efforts have been made to prevent and manage chronic constipation in these patients., Areas Covered: Herein, the authors review some of the known pathophysiological causes for slow gastrointestinal (GI) transit in PD patients and the different pharmacological options. All relevant clinical and experimental data found through online databases were included. Bulking agents, osmotic and stimulant laxatives, chloride channel activators, ghrelin agonists, 5-HT4 receptor agonists, and probiotics are some of the proposed medicinal agents. of the authors further review the evidence on alpha-synuclein and botulinum neurotoxin in these patients. It should be noted, however, that some of these interventions are required to be further validated., Expert Opinion: Reduction of GI transit and dysfunction of the anorectum is obvious in PD, affecting the incidence of constipation and thus, quality of life (QOL). Furthermore, due to an inadequate and delayed absorption of oral anti PD medications, dose adjustments and changes in the route of administration are recommended.

The latest estimates from world health organization suggest that more than 450 million people are suffering from depression and other psychiatric conditions. Of these, 50-60% have been reported to have progression of gut diseases. In the last two decades, researchers introduced incipient physiological roles for serotonin (5-HT) receptors (5-HTRs), suggesting their importance as a potential pharmacological target in various psychiatric and gut diseases. A growing body of evidence suggests that 5-HT systems affect the brain-gut axis in depressive patients, which leads to gut comorbidity. Recently, preclinical trials of 5-HT4R agonists and antagonists were promising as antipsychotic and prokinetic agents. In the current review, we address the possible pharmacological role and contribution of 5-HT4R in the pathophysiology of chronic depression and associated gut abnormalities. Physiologically, during depression episodes, centers of the sympathetic and parasympathetic nervous system couple together with neuroendocrine systems to alter the function of hypothalamic-pituitary-adrenal (HPA) axis and enteric nervous system (ENS), which in turn leads to onset of gastrointestinal tract (GIT) disorders. Consecutively, the ENS governs a broad spectrum of physiological activities of gut, such as visceral pain and motility. During the stages of emotional stress, hyperactivity of the HPA axis alters the ENS response to physiological and noxious stimuli. Consecutively, stress-induced flare, swelling, hyperalgesia and altered reflexes in gut eventually lead to GIT disorders. In summary, the current review provides prospective information about the role and mechanism of 5-HT4R-based therapeutics for the treatment of depressive disorder and possible consequences for the gut via brain-gut axis interactions. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'., Competing Interests: Declaration of competing interest Authors declare no competing interest associated with manuscript. All the authors read and approved the final manuscript., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Functional constipation is common in children and adults worldwide. Functional constipation shows similarities in children and adults, but important differences also exist regarding epidemiology, symptomatology, pathophysiology, diagnostic workup and therapeutic management. In children, the approach focuses on the behavioural nature of the disorder and the initial therapeutic steps involve toilet training and laxatives. In adults, management focuses on excluding an underlying cause and differentiating between different subtypes of functional constipation - normal transit, slow transit or an evacuation disorder - which has important therapeutic consequences. Treatment of adult functional constipation involves lifestyle interventions, pelvic floor interventions (in the presence of a rectal evacuation disorder) and pharmacological therapy. When conventional treatments fail, children and adults are considered to have intractable functional constipation, a troublesome and distressing condition. Intractable constipation is managed with a stepwise approach and in rare cases requires surgical interventions such as antegrade continence enemas in children or colectomy procedures for adults. New drugs, including prokinetic and prosecretory agents, and surgical strategies, such as sacral nerve stimulation, have the potential to improve the management of children and adults with intractable functional constipation.

Previously, we found that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) model mice (PD mice) showed facilitation of hippocampal memory extinction via reduced cyclic adenosine monophosphate (cAMP)/cAMP-dependent response element-binding protein (CREB) signaling, which may cause cognitive impairment in PD. Serotonergic neurons in the median raphe nucleus (MnRN) project to the hippocampus, and functional abnormalities have been reported. In the present study, we investigated the effects of the serotonin 5-HT 4 receptor (5-HT 4 R) agonists prucalopride and velusetrag on the facilitation of memory extinction observed in PD mice. Both 5-HT 4 R agonists restored facilitation of contextual fear extinction in PD mice by stimulating the cAMP/CREB pathway in the dentate gyrus of the hippocampus. A retrograde fluorogold-tracer study showed that γ-aminobutyric acid-ergic (GABAergic) neurons in the reticular part of the substantia nigra (SNr), but not dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNpc), projected to serotonergic neurons in the MnRN, which are known to project their nerve terminals to the hippocampus. It is possible that the degeneration of the SNpc DAergic neurons in PD mice affects the SNr GABAergic neurons, and thereafter, the serotonergic neurons in the MnRN, resulting in hippocampal dysfunction. These findings suggest that 5HT4R agonists could be potentially useful as therapeutic drugs for treating cognitive deficits in PD.

The prokinetic effects of 5-HT 4 receptor (5-HT 4 R) agonists have been utilized clinically for almost three decades to relieve symptoms of constipation. Surprisingly, the mechanism(s) of action of these compounds is still being debated. Recent studies highlight luminal 5-HT 4 Rs as an alternative and effective target for these prokinetic agents. These include the study by Shokrollahi et al (2019, Neurogastroenterol Motil, e13598) published in the current issue of Neurogastroenterology and Motility, who found that activation of mucosal 5-HT 4 Rs by intraluminal prucalopride, significantly enhanced propulsive motor patterns in rabbit colon. The authors highlight the idea that development of agonists targeting luminal 5-HT 4 Rs in the colonic mucosa might be more effective and safer in achieving prokinetic effects on intestinal motility. The purpose of this mini-review is to discuss the evidence for luminal 5-HT 4 Rs as an emerging target for prokinetic agents in facilitating propulsive motor patterns in the colon., (© 2019 John Wiley & Sons Ltd.)

Objectives: Prokinetics are considered the preferred treatment option for gastroparesis, but evidence of their efficacy is scarce. Prucalopride, a selective 5-hydroxytryptamine 4 receptor agonist used in the treatment of constipation, is able to enhance the gastric emptying rate. In a double-blind, randomized, placebo-controlled crossover study, we evaluated the efficacy of prucalopride to improve the gastric emptying rate and symptoms in patients with gastroparesis., Methods: Thirty-four patients with gastroparesis (28 idiopathic, 7 men, mean age 42 ± 13 years) were evaluated in a double-blind crossover trial of 4-week treatment periods with placebo or prucalopride 2 mg q.d., separated by 2 weeks of washout. The primary end point was the change in symptom severity, assessed by the Gastroparesis Cardinal Symptom Index; secondary end points comprised the Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index, the Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life, and daily diaries, and the gastric emptying rate was assessed by the C-octanoic acid breath test., Results: Three patients were lost to follow-up. One serious adverse event occurred (small bowel volvulus in the prucalopride group), and 3 patients dropped out because of adverse events of nausea and headache (all prucalopride). For the entire patient group, compared with placebo, prucalopride significantly improved the total Gastroparesis Cardinal Symptom Index (1.65 ± 0.19 vs 2.28 ± 0.20, P < 0.0001) and the subscales of fullness/satiety, nausea/vomiting, and bloating/distention. Prucalopride significantly improved the overall Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life score (1.15 ± 0.16 vs 1.44 ± 0.16, P < 0.05) and the domains of clothing and diet. The gastric half emptying time was significantly enhanced by prucalopride compared with placebo and baseline (98 ± 10 vs 143 ± 11 and 126 ± 13 minutes, P = 0.005 and <0.001, respectively). These significant improvements were also found when considering only the idiopathic gastroparesis subgroup., Discussion: In a cohort of patients with predominantly idiopathic gastroparesis, 4 weeks of prucalopride treatment significantly improved symptoms and quality of life and enhanced gastric emptying compared with placebo.

Introduction : Prucalopride is a selective 5-HT 4 receptor agonist with colonic prokinetic activity. It was recently approved by the FDA for the treatment of chronic idiopathic constipation. Before this approval, there were limited options to improve colonic motility in the treatment of chronic idiopathic constipation. Areas covered : We systematically searched PubMed, Embase, ClinicalTrials.gov, and international conference presentations, and we reviewed all studies that evaluated prucalopride for the treatment of chronic idiopathic constipation in adults. In this review, we discuss the pharmacokinetics, pharmacodynamics, receptor interactions, phase I-IV clinical trials, and safety outcomes of prucalopride in adults, including the elderly. Expert opinion : Prucalopride is an effective agent to improve colonic motility, decrease colonic transit time, and increase complete spontaneous bowel movements in patients with chronic idiopathic constipation. Unlike previously available 5-HT 4 receptor agonists such as cisapride and tegaserod, prucalopride does not interact with the cardiac hERG potassium channels or other serotonergic receptors in blood vessels and is not associated with an increase in major adverse cardiovascular events. Additionally, prucalopride has demonstrated promise in the treatment of gastroparesis, post-operative ileus, and opioid-induced constipation. Prucalopride directly stimulates colonic motility, differentiating it from all other medications (exclusively osmotic or chloride secretagogues) approved for chronic constipation in the last decade.

Background & Aims: Studies have reported a lack of association between improvements in gastric emptying (GE) and upper gastrointestinal (UGI) symptoms with promotility drugs. However, GE test methods were suboptimal in some studies. We assessed improvements in GE and UGI symptoms in patients given promotility agents in studies with optimal or moderate test methods (scintigraphy or breath test, solid meal, >2 hours duration) compared to studies with suboptimal GE test methods., Methods: With an expert librarian, we completed an extensive search of publications in the Ovid MEDLINE (1946 to present), EMBASE (1988 to January 2018), and EBM Reviews Cochrane Central Register of Controlled Trials, without restrictions on language or year. Two independent reviewers evaluated the following inclusion criteria: randomized, blinded, parallel, or crossover trials of 5HT 4 agonists, D 2 receptor antagonist, or ghrelin agonists; trials that measured change in GE (T 1/2 ) or composite UGI symptoms; trials of patients with functional dyspepsia and gastroparesis; and trials of GE test methods. Standardized mean differences (units expressed as SD) were used to standardize symptom assessments that were not uniform across studies. Random effects model was used to analyze data and meta-regression was used to evaluate the association between change in GE and UGI symptoms., Results: Of 899 studies considered, 22 studies assessed change in GE; 23 evaluated UGI symptoms; and 14 evaluated GE and UGI symptoms. Promotility agents significantly accelerated GE (T 1/2 ) in all studies (mean reduction in T 1/2 , 16.3 minutes; 95% confidence interval, -22.1 to -10.6 minutes) and in studies that used optimal GE test methods (mean reduction in T 1/2 , 23.6 minutes; 95% confidence interval, -32.3 to -14.9 minutes). Promotility agents also significantly reduced UGI symptoms (mean reduction, 0.25 SD; 95% confidence interval, -0.37 to -0.13 SD). Meta-regression found no significant association between change in GE and UGI symptoms. However, when only studies with optimal GE test methods were evaluated, there was a significant positive association between improvement in GE and UGI symptoms (P = .02)., Conclusions: In a meta-analysis of published trials, we found promotility agents to significantly accelerate GE (when optimal test methods were used) and to produce significant improvements in UGI symptoms., (Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Introduction: Prucalopride is a prokinetic drug, that has been commercially available in recent years for the treatment of chronically constipated patients. In this update of a previous 2016 article, we reviewed the more recent data supporting its role in the treatment of constipation and constipation-associated conditions. Areas covered: We carried out an extensive literature review on the effects of prucalopride for the years 2012-2018 by means of scientific databases and manual research. More evidence was found on its possible therapeutic role in conditions in which constipation plays a role as an associated symptom, such as opioid-induced constipation, constipation-predominant irritable bowel syndrome, post-operative ileus, colonic diverticular disease, drug-related constipation, and chronic intestinal pseudo-obstruction. Expert opinion: Based on the added literature evidence, we feel that prucalopride is an effective, although expensive, drug for the treatment of primary and secondary forms of constipation, and of other clinical conditions associated with constipation.

Constipation is a common functional problem of the digestive system and may occur secondary to diet, drugs, endocrine diseases, metabolic diseases, neurological diseases, psychiatric disorders, or gastrointestinal obstruction. When there is no secondary cause, constipation is diagnosed as functional constipation. The first steps that should be taken to relieve symptoms are diet and lifestyle modifications, and if unsuccessful, laxative therapy should be initiated. If a patient does not respond to laxative therapy, diagnostic anorectal physiological tests are performed, though they are not routinely recommended. However, these tests may be considered earlier in patients strongly suspected to have a defecatory disorder. The revised guideline on the diagnosis and treatment of chronic constipation will undoubtedly aid the individualized management of chronic constipation in clinical practice.

The pharmacological profile of DSP-6952, a novel 5-HT 4 receptor partial agonist, was investigated to evaluate the potential use for GI disorders, and to compare its effects in some GI dysfunction models with those of clinically efficacious prokinetic agents. DSP-6952 enhanced gastric motility and caused colonic giant migrating contractions (GMCs) associated with defecation in conscious dogs, having ED 50 value for inducing GMCs of 1.56 mg/kg. DSP-6952 (3-10 mg/kg, i.g.) significantly enhanced colonic transit rate in guinea pigs; this enhancement was antagonized by SB-207266, a selective 5-HT 4 receptor antagonist. DSP-6952 (1-10 mg/kg, p.o.) rapidly increased fecal wet weight without increasing fluid content in mice. Sennoside (30-100 mg/kg, p.o.) also increased fecal wet weight; however, it significantly increased fluid content with diarrhea. DSP-6952 dose-dependently improved clonidine- and morphine-induced delay in whole-gut transit in mice (ED 50 = 0.429 mg/kg and 0.310 mg/kg, respectively), which represented atonic and spastic constipation models, respectively. In viscerally hypersensitive rats treated with acetic acid, DSP-6952 (10 mg/kg, i.p., 30 mg/kg, p.o., 30 mg/kg, i.c.) and tegaserod (1 mg/kg, i.p.), but not prucalopride (10 mg/kg, i.p.), significantly inhibited the increase in colorectal distension-induced visceromotor response; these findings suggest that DSP-6952 and tegaserod inhibit visceral hypersensitivity in rats. It was concluded that DSP-6952, a novel and orally available 5-HT 4 receptor agonist, induced colonic GMCs, enhanced colonic transit, increased defecation without inducing diarrhea, improved drug-induced delay in whole-gut transit, and inhibited visceral hypersensitivity in experimental animals. Therefore, DSP-6952 is expected to become a useful drug for treatment of IBS-C and chronic constipation., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Aim: Ineffective esophageal motility (IEM) is associated with gastroesophageal reflux disease. Secondary peristalsis contributes to esophageal clearance. Prucalopride promotes secondary peristalsis by stimulating 5-hydroxytrypatamine 4 receptors in the esophagus. We aimed to determine whether prucalopride would augment secondary peristalsis in gastroesophageal reflux disease patients with IEM., Methods: After a baseline recording of primary peristalsis, secondary peristalsis was stimulated by slow and rapid mid-esophageal injections of air in 15 patients with IEM. Two separate sessions with 4-mg oral prucalopride or placebo were randomly performed., Results: Prucalopride significantly increased primary peristaltic wave amplitude (68.1 ± 10.0 vs 55.5 ± 8.8 mmHg, P = 0.02). The threshold volume for triggering secondary peristalsis was significantly decreased by prucalopride during slow (9.3 ± 0.8 vs 12.0 ± 0.8 mL; P = 0.04) and rapid air injection (4.9 ± 0.3 vs 7.1 ± 0.1 mL; P = 0.01). Secondary peristalsis was triggered more frequently after application of prucalopride (55% [43-70%]) than placebo (45% [33-50%]) (P = 0.008). Prucalopride did not change pressure wave amplitudes during slow air injection (84.6 ± 8.1 vs 57.4 ± 13.8 mmHg; P = 0.19) or pressure wave amplitudes during rapid air injection (84.2 ± 8.6 vs 69.5 ± 12.9 mmHg; P = 0.09)., Conclusions: Prucalopride enhances primary peristalsis and mechanosensitivity of secondary peristalsis with limited impact on secondary peristaltic activities in IEM patients. Our study suggests that prucalopride appears to be useful in augmenting secondary peristalsis in patients with IEM only via sensory modulation of esophageal secondary peristalsis., (© 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background: Irritable bowel syndrome (IBS) is a chronic, recurrent bowel disorder with an unknown etiology, which is most likely multifactorial. Increased mucosal permeability, visceral hypersensitivity and activation status of intestinal mucosal immune cells cause changes in gastrointestinal (GI) motility, secretion and sensation observed in the course of IBS. Permanent, cumbersome symptoms, such as diarrhea, constipation and abdominal pain greatly lower the quality of life of IBS patients. On this basis, according to the Rome IV criteria, different forms of IBS can be distinguished., Objective: This article focuses on the role of serotonin system in the pathophysiology of IBS as a potential therapeutic target. We shortly describe several molecules, associated with serotonin receptors, mainly 5-HT3 receptor antagonists and 5-HT4 receptor agonists, that are used in the treatment of motility disorders and visceral pain in IBS patients. We summarize the findings obtained in the clinical trials and elaborate on the safety of the serotonin ligands. Although the majority of serotonin receptor ligands relieve global symptoms, there are also some adverse effects, which can be dangerous for patients., Results and Conclusion: We postulate that currently, among all serotonin-targeting compounds, ramosetron is the best treatment option for IBS-D patients, due to its exceptional efficacy in both genders as well as good tolerability. Whereas, tegaserod is highly recommended for IBS-C sufferers. Nevertheless, numerous studies on the new serotonin receptor ligands are conducted to ensure the delivery of novel compounds with improved efficacy and safety profiles., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Chronic constipation is one of the most common digestive diseases frequently observed in a clinical setting. It has been known to cause considerable damage to the quality of life of patients. Despite recent developments, there are considerable limitations in the use of constipation-modulating agents in Korea. Chloride channel inhibitors, such as lubiprostone and linaclotide, have not been introduced in Korea yet, and prucalopride and several kinds of polyethylene glycol are not covered under medical insurance. This article assesses medicines that are clinically available for the management of constipation in Korea, with a brief review of agents that have recently developed around the world.

Introduction: Postoperative ileus (POI) is an impairment of coordinated gastrointestinal (GI) motility that develops as a consequence of abdominal surgery and is a major factor contributing to patient morbidity and prolonged hospitalisation. Despite the availability of various options its treatment is still under debate. This review will focus on effect of Prucalopride (5-HT 4 receptor agonist) on postoperative ileus based on the existing literature. Areas covered: A literature search of MEDLINE, EMBASE and COCHRANE Library was performed concerning topics related to the treatment of ileus with prucalopride. The search strategy also included articles relating to other treatments of ileus for comparison with prucalopride. Expert opinion: Postoperative ileus remains difficult to treat and most strategies encompass preventative measures through enhanced recovery after surgery and laparoscopic approaches. The role of pharmacological intervention is developing with some drugs licensed for use. The evidence for prucalopride remains unclear although there is randomised controlled trial (RCT) evidence available. Given the potential for reduction in patient morbidity and length of stay the role of prucalopride in POI should be further investigated with multi-centre RCTs to establish which group of patients will gain the most from this exciting potential treatment.

Background . Chronic idiopathic constipation (CIC) and constipation-predominant irritable bowel syndrome (IBS-C) are common functional lower gastrointestinal disorders that impair patients' quality of life. In a national survey, we aimed to evaluate (1) Canadian physician practice patterns in the utilization of therapeutic agents listed in the new ACG and AGA guidelines; (2) physicians satisfaction with these agents for their CIC and IBS-C patients; and (3) the usefulness of these new guidelines in their clinical practice. Methods . A 9-item questionnaire was sent to 350 Canadian specialists to evaluate their clinical practice for the management of CIC and IBS-C. Results . The response rate to the survey was 16% ( n = 55). Almost all (96%) respondents followed a standard, stepwise approach for management while they believed that only 24% of referring physicians followed the same approach. Respondents found guanylyl cyclase C (GCC) agonist most satisfying when treating their patients. Among the 69% of respondents who were aware of published guidelines, only 50% found them helpful in prioritizing treatment choices and 69% of respondents indicated that a treatment algorithm, applicable to Canadian practice, would be valuable. Conclusion . Based on this needs assessment, a treatment algorithm was developed to provide clinical guidance in the management of IBS-C and CIC in Canada., Competing Interests: Dr. Yvonne Tse has received honorarium for participation in advisory boards from AbbVie. Dr. David Armstrong has received research funding from AbbVie; honoraria for participation in advisory boards and/or speaking at educational events from AbbVie, Allergan, Cubist, Ferring, Hospira, Janssen, Lupin, Pendopharm, Pentax, Pfizer, Shire, and Takeda; sponsorship for educational events from AbbVie, Allergan, Boston Scientific, Cook Medical, Ferring, Hospira, Janssen, Lupin, Olympus, Pendopharm, Shire, and Takeda. Dr. Christopher Andrews has received research funding from Janssen and Allergan and honoraria from Allergan, Pendopharm, Lupin, and AbbVie. Dr. Alain Bitton has received honorarium for participation in advisory boards from Allergan. Dr. Brian Bressler has received research funding from AbbVie, Amgen, Takeda, BMS, Genentech, Janssen, BI, GSK, Redhill Biopharm, Celgene, and Merck; honoraria for participation in advisory boards and/or speaking at educational events from AbbVie, Janssen, Takeda, Shire, Pendopharm, Ferring, Pfizer, Amgen, and Merck; honoraria for providing consulting service from Genentech, Pendopharm, and Allergan. Dr. John Marshall has received honoraria for participation in speaking at educational events from AbbVie, Allergan, Ferring, Janssen, Procter & Gamble, Shire, and Takeda and honoraria for providing consulting service from AbbVie, Allergan, Astra-Zeneca, Boehringer-Ingelheim, Celgene, Celltrion, Ferring, Hospira, Janssen, Merck, Pfizer, Pharmascience, Procter & Gamble, Shire, and Takeda. Dr. Louis Liu has received honoraria for participation in advisory boards and/or speaking at educational events from Takeda, AbbVie, Allergan, and Lupin and honorarium for providing consulting service from Allergan.

Background & Aims: The 5-hydroxytryptamine receptor 4 (5-HT 4 R or HTR 4 ) is expressed in the colonic epithelium but little is known about its functions there. We examined whether activation of colonic epithelial 5-HT 4 R protects colons of mice from inflammation., Methods: The 5-HT 4 R agonist tegaserod (1 mg/kg), the 5-HT 4 R antagonist GR113808 (1 mg/kg), or vehicle (control) were delivered by enema to wild-type or 5-HT 4 R knockout mice at the onset of, or during, active colitis, induced by administration of dextran sodium sulfate or trinitrobenzene sulfonic acid. Inflammation was measured using the colitis disease activity index and by histologic analysis of intestinal tissues. Epithelial proliferation, wound healing, and resistance to oxidative stress-induced apoptosis were assessed, as was colonic motility., Results: Rectal administration of tegaserod reduced the severity of colitis compared with mice given vehicle, and accelerated recovery from active colitis. Rectal tegaserod did not improve colitis in 5-HT 4 R knockout mice, and intraperitoneally administered tegaserod did not protect wild-type mice from colitis. Tegaserod increased proliferation of crypt epithelial cells. Stimulation of 5-HT 4 R increased Caco-2 cell migration and reduced oxidative stress-induced apoptosis; these actions were blocked by co-administration of the 5-HT 4 R antagonist GR113808. In noninflamed colons of wild-type mice not receiving tegaserod, inhibition of 5-HT 4 Rs resulted in signs of colitis within 3 days. In these mice, epithelial proliferation decreased and bacterial translocation to the liver and spleen was detected. Daily administration of tegaserod increased motility in inflamed colons of guinea pigs and mice, whereas administration of GR113808 disrupted motility in animals without colitis., Conclusions: 5-HT 4 R activation maintains motility in healthy colons of mice and guinea pigs, and reduces inflammation in colons of mice with colitis. Agonists might be developed as treatments for patients with inflammatory bowel diseases., Competing Interests: Discolosures The authors have no conflicts to disclose., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

5-HT4 receptor (5-HT4R) activation and blockade of the 5-HT6 receptor (5-HT6R) are known to enhance the release of numerous neurotransmitters whose depletion is implicated in Alzheimer's disease (AD). Furthermore, 5-HT4R agonists seem to favor production of the neurotrophic soluble amyloid protein precursor alpha (sAPPα). Consequently, combining 5-HT4R agonist/5-HT6R antagonist activities in a single chemical compound would constitute a novel approach able to display both a symptomatic and disease-modifying effect in AD. Seventeen novel derivatives of RS67333 (1) were synthesized and evaluated as potential dual-target compounds. Among them, four agents showed nanomolar and submicromolar affinities toward 5-HT4R and 5-HT6R, respectively; one of them, 7m, was selected on the basis of its in vitro affinity (Ki5-HT4R = 5.3 nM, Ki5-HT6R = 219 nM) for further in vivo experiments, where 7m showed an antiamnesic effect in the mouse at 1 mg/kg ip., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: This study compared prucalopride, a selective, prokinetic, 5-HT4 receptor agonist, with polyethylene glycol 3350 + electrolytes (PEG3350), an osmotic laxative, on colonic motility parameters, primarily high-amplitude propagating contractions (HAPCs) in patients with chronic constipation., Methods: This randomized, cross-over, reader-blinded study was conducted at a single site in the USA. The study was open to men and women aged 18-75 years who met study inclusion criteria. Colonic manometry catheters were inserted the day before investigation. On the investigation days, patients received oral 2 mg prucalopride or 2 × 13.8 g PEG3350 in solution. The primary endpoint was HAPC count (threshold: mean amplitude ≥100 mmHg, propagation ≥20 cm [HAPC1 ]) in the 12 h after treatment administration. Analyses were also conducted at two co-primary thresholds: mean amplitude ≥75 mmHg, propagation ≥20 cm (HAPC2 ); and mean amplitude ≥75 mmHg, propagation ≥10 cm (HAPC3 ). Secondary endpoints included HAPC area under the curve (AUC), contraction force, amplitude, duration, and propagation velocity., Key Results: Thirteen women were enrolled, with 12 completing the study. Significantly more HAPC1 (8.7 ± 2.06 vs 2.9 ± 2.06; p = 0.012) and HAPC2 (9.0 ± 2.11 vs 3.3 ± 2.11; p = 0.017) were observed in the 12-h periods with prucalopride than with PEG3350. Prucalopride significantly increased mean propagation distance and velocity (HAPC2 ) and mean AUC, force, and amplitude (HAPC3 ) compared with PEG3350. Adverse events were mild or moderate., Conclusions & Inferences: Prucalopride was superior to PEG3350 in inducing HAPCs in patients with chronic constipation. ClinicalTrials.gov number NCT01707667., (© 2016 Shire Development LLC Neurogastroenterology & Motility Published by John Wiley & Sons Ltd.)

Background: Prucalopride, a selective, high-affinity 5-hydroxytryptamine 4 receptor agonist, stimulates gastrointestinal and colonic motility and alleviates common symptoms of chronic constipation (CC) in adults. The relative efficacy by gender has not been evaluated., Aim: To evaluate the global efficacy and safety of prucalopride 2 mg daily in men and women with CC using data from six large, randomized, controlled clinical trials., Methods: Data were combined from six phase 3 and 4, double-blind, randomized, placebo-controlled, parallel-group trials. The primary efficacy endpoint was the percentage of patients with a mean of ≥3 spontaneous complete bowel movements (SCBMs) per week over 12 weeks of treatment. Safety was assessed throughout all the trials., Results: Overall, 2484 patients (597 men; 1887 women; prucalopride, 1237; placebo, 1247) were included in the integrated efficacy analysis and 2552 patients were included in the integrated safety analysis. Significantly more patients achieved a mean of ≥3 SCBMs/week over the 12 weeks of treatment in the prucalopride group (27.8 %) than in the placebo group [13.2 %, OR 2.68 (95 % CI 2.16, 3.33), p < 0.001]. Prucalopride had a favorable safety and tolerability profile. Efficacy and safety outcomes were not significantly different between men and women., Conclusion: The integrated analysis demonstrates the efficacy and safety of prucalopride in the treatment of CC in men and women.

Introduction: Chronic constipation is a frequent complaint in daily clinical practice. Notwithstanding the availability of numerous drugs, its treatment it is still unsatisfactory. However, new emerging treatments are in the pipeline and some drugs seem to be promising; among these velusetrag, a selective 5-HT4 receptors agonist., Areas Covered: An in depth Medline literature search was performed concerning topics related to the treatment of constipated patients with velusetrag. In addition, abstracts concerning the topic were searched by hand in our libraries., Expert Opinion: After analyzing the available data, the authors feel that velusetrag may likely improve symptoms and the quality of life of chronically constipated subjects. However, additional data is needed to fully understand the safety and efficacy of velusetrag, particularly in patients on long-term therapy. Thanks to the once-daily dosing and the pharmacologic properties, velusetrag could be used as a single agent or in association with other drugs. In the future, this drug holds the potential to be an effective adjunct to the therapeutic armamentarium for chronic constipation.

Prucalopride is a new prokinetic agent, recently available in Europe for the treatment of functional constipation in adults in whom treatment with laxatives failed to provide adequate relief. However, due to its intrinsic properties (highly selective agonist activity and high affinity for 5-HT4 receptors, neuroprotection), this drug has shown the potential to be used in other pathologic conditions, in and outside of the gastrointestinal tract. We performed a systematic review of the evidence supporting these possible alternative uses of prucalopride. Further studies in this area are, however, mandatory.

Cognitive disturbances are often reported as serious invalidating symptoms in patients suffering from major depression disorders (MDD) and are not fully corrected by classical monoaminergic antidepressant drugs. If the role of 5-HT4 receptor agonists as cognitive enhancers is well established in naïve animals or in animal models of cognitive impairment, their cognitive effects in the context of stress need to be examined. Using a mouse model of anxiety/depression (CORT model), we reported that a chronic 5-HT4 agonist treatment (RS67333, 1.5mg/kg/day) restored chronic corticosterone-induced cognitive deficits, including episodic-like, associative and spatial learning and memory impairments. On the contrary, a chronic monoaminergic antidepressant drug treatment with fluoxetine (18mg/kg/day) only partially restored spatial learning and memory deficits and had no effect in the associative/contextual task. These results suggest differential mechanisms underlying cognitive effects of these drugs. Finally, the present study highlights 5-HT4 receptor stimulation as a promising therapeutic mechanism to alleviate cognitive symptoms related to MDD., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Prucalopride (Resolor®), a highly selective serotonin 5-HT4 receptor agonist, is indicated in the European Economic Area for the treatment of adults with chronic idiopathic constipation (CIC) in whom laxatives have failed to provide adequate relief. This article reviews the pharmacological properties of prucalopride and its clinical efficacy and tolerability in patients with CIC. In five well-designed, 12-week trials in patients with CIC, oral prucalopride 2 mg/day was significantly more effective than placebo at improving bowel function, including the number of bowel movements and a range of other constipation symptoms, as well as health-related quality of life and patient satisfaction; however, no significant differences in bowel function measures were observed between prucalopride and placebo in a 24-week trial. Oral PEG-3350 + electrolytes reconstituted powder was found to be noninferior but not superior to prucalopride according to primary endpoint data from a 4-week, controlled-environment trial. Prucalopride was generally well tolerated in clinical trials; the most common adverse events were headache, diarrhoea, nausea and abdominal pain. No cardiovascular safety issues have arisen with prucalopride treatment. Although further long-term and comparative data would be beneficial, prucalopride provides an additional treatment option for patients with CIC.

Constipation is a disorder frequently complained about by patients in daily clinical practice. However, to date, its treatment is still commonly unsatisfactory, especially concerning patients' quality of life, when using conventional measures. Prucalopride, a selective 5-hydroxytryptamine receptor 4 agonist, was introduced to the market in 2009 and has been commercially available in Europe since 2010. The main effect of prucalopride is to stimulate colonic motility, which explains its efficacy to treat constipated patients unresponsive to other regimens. Literature search was carried out to look for effects of prucalopride on constipated patients. Several papers were found demonstrating that prucalopride is effective in treatment of constipated patients. Due to its few side effects, the lack of cardiovascular effects and interactions with other drugs, prucalopride may be safely used in elderly people as well.

Irritable bowel syndrome (IBS) affects about 15 % of the US population and results in significant morbidity and health care costs. There remains a significant unmet need for effective treatments particularly for the pain component of IBS and other functional gastrointestinal disorders (FGIDs). Progress made in our understanding of pathophysiological mechanisms such as the role of altered bile acid metabolism, neurohormonal regulation, immune dysfunction, the epithelial barrier and secretory properties of the gut has led to advancements in therapeutic armamentarium for IBS. This review discusses the new drugs for constipation and diarrhea-predominant IBS subtypes that have been tested or have been under investigation over the last 3-4 years. Overall, there is a promising pipeline of investigational drugs for the future treatment of IBS and related FGIDs.

Alzheimer's disease (AD) is the most common form of dementia affecting 35 million individuals worldwide. Current AD treatments provide only brief symptomatic relief. It is therefore urgent to replace this symptomatic approach with a curative one. Increasing serotonin signaling as well as developing molecules that enhance serotonin concentration in the synaptic cleft have been debated as possible therapeutic strategies to slow the progression of AD. In this Viewpoint, we discuss exciting new insights regarding the modulation of serotonin signaling for AD prevention and therapy.

Background: Randomized trials have confirmed the efficacy of prucalopride for the treatment of chronic constipation up to 12 weeks. This study aimed to assess the efficacy of prucalopride over a 24-week period (ClinicalTrials.gov: NCT01424228)., Methods: Adults with chronic constipation and ≤2 spontaneous complete bowel movements (SCBMs)/week were randomized to receive prucalopride 2 mg or placebo daily for 24 weeks. The primary endpoint was the proportion of patients achieving a mean of ≥3 SCBMs/week over the treatment period, assessed using daily e-diaries. Secondary outcomes and safety parameters were assessed throughout the study., Key Results: Overall, 361 patients were randomized and received prucalopride or placebo. Baseline characteristics were similar in the prucalopride (N = 181) and placebo (N = 180) groups. Mean age was 48.9 years (standard deviation, 16.0) and most patients were women. The proportion of participants achieving the primary endpoint was not statistically different between the prucalopride and placebo groups (25.1% vs 20.7%; p = 0.367). There was also no statistically significant difference between groups over the first 12-week period (prucalopride, 25.1%; placebo, 20.1%; p = 0.341). There were no statistically significant differences between groups for most secondary endpoints. No new safety concerns were identified., Conclusions & Inferences: This trial did not show statistically significant improvements in primary or secondary outcomes with prucalopride compared with placebo over 24 or 12 weeks. This is in contrast to the results of four previous 12-week trials, which demonstrated prucalopride to be significantly more effective than placebo. An extensive evaluation did not provide an explanation for the null efficacy results of this study., (© 2015 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Objectives: Prucalopride is effective at alleviating symptoms of chronic constipation in women. The aim of this study was to assess the efficacy of 12 weeks of prucalopride treatment compared with placebo in men with chronic constipation., Methods: This was a multicenter, stratified, randomized, parallel-group, double-blind, placebo-controlled, phase 3 study (ClinicalTrials.gov identifier: NCT01147926). The primary end point was the proportion of patients with a mean of three or more spontaneous complete bowel movements (SCBMs) per week across the treatment period. Efficacy end points were assessed using daily electronic diaries, global assessment of the severity of constipation and efficacy of treatment, and Patient Assessment of Constipation-Symptoms (PAC-SYM) and Patient Assessment of Constipation-Quality of Life (PAC-QOL) questionnaires., Results: In total, 374 patients were enrolled in the study. Significantly more patients achieved a mean of three or more SCBMs per week in the prucalopride group (37.9%) than in the placebo group (17.7%, P<0.0001). The proportion of patients rating their constipation treatment as "quite a bit" to "extremely" effective at the final on-treatment visit was 46.7 and 30.4% in the prucalopride and placebo groups, respectively. The difference between treatment groups was statistically significant (P<0.0001). The proportion of patients with an improvement of at least 1 point in PAC-QOL satisfaction subscale score was 52.7 and 38.8% in the prucalopride and placebo groups, respectively (P=0.0035). Prucalopride had a good safety profile and was well tolerated., Conclusions: Prucalopride is effective, has a good safety profile, and is well tolerated for the treatment of men with chronic constipation.

Background: A substantial proportion of patients with gastro-oesophageal reflux disease (GERD) have only a partial response to proton pump inhibitor (PPI) therapy. Prokinetic drugs may improve reflux symptoms by enhancing oesophageal motility and gastric emptying., Aim: To evaluate the effect of revexepride, a novel prokinetic 5-hydroxytryptamine type 4 (5-HT4 ) receptor agonist, compared with placebo, in patients with GERD who have a partial response to PPIs., Methods: A phase 2b, double-blind, parallel-group study was conducted, in which patients were randomised to one of three revexepride treatment groups (0.1, 0.5 and 2.0 mg three times daily) or placebo (1:1:1:1 ratio). Daily e-diary data captured patients' symptoms over an 8-week treatment period. The primary efficacy outcome was the weekly percentage of regurgitation-free days in the second half of the study (weeks 5-8)., Results: In total, 480 patients were randomised and 477 received treatment (mean age 47.9 years; 61% women). The mean percentage of regurgitation-free days increased from baseline (range, 15.0-18.8%) to week 8 (62.3-70.5%) in all four study arms; however, there were no statistically significant differences in this change between placebo and the three treatment arms. No dose-dependent relationship in treatment effect was observed for any of the study endpoints. The incidence of treatment-emergent adverse events (TEAEs) was revexepride dose-dependent. Only one serious TEAE occurred and none resulted in death., Conclusions: Revexepride was no more effective than placebo in controlling regurgitation in patients with GERD symptoms partially responsive to PPIs. Revexepride was well tolerated. ClinicalTrials.gov Identifier: NCT01472939., (© 2015 Shire Development LLC. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

Background: Prucalopride is a high-affinity 5-HT4 receptor agonist for the treatment of chronic constipation. The aims of this study were to investigate the relationship between health-related quality of life (HRQoL) and symptoms of constipation, and to assess the response of HRQoL to treatment using integrated data from three phase III trials of prucalopride., Methods: This was an integrated analysis of data from three pivotal multicenter, double-blind, randomized, placebo-controlled, parallel-group trials (ClinicalTrials.gov Identifiers: NCT00488137, NCT00483886 and NCT00485940). Relationships were investigated between Patient Assessment of Constipation Quality of Life (PAC-QOL) scores, Patient Assessment of Constipation Symptoms (PAC-SYM) scores, bowel movement frequency (assessed using daily diaries), and treatment., Key Results: Patients treated with prucalopride 2 mg (n = 659) and placebo (n = 661) were included in the analysis. An improvement in PAC-SYM scores correlated well with an improvement in PAC-QOL overall score (r = 0.711) and satisfaction subscale score (r = 0.589). After 12 weeks, PAC-QOL overall score and satisfaction subscale score significantly (p < 0.001) improved by ≥ 1 point (clinically relevant) in 36.5% and 44.1% of patients treated with prucalopride, compared with 18.5% and 22.4% with placebo respectively. Moreover, 39.0% of patients with an improvement in satisfaction of ≥ 1 point achieved ≥ 3 spontaneous complete bowel movements/week, compared with 7.4% of those with no improvement in satisfaction (<1 point)., Conclusions & Inferences: Improvements in PAC-QOL overall score and satisfaction score were associated with improvements in symptoms of chronic constipation. Compared with placebo, treatment with prucalopride significantly improved HRQoL., (© 2015 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Introduction: Chronic constipation (CC) is a debilitating condition with high prevalence rates both in children and adults. Despite the broad range of medical and pharmaceutical treatments, the bowel function does not restore in a fair amount of patients. Prucalopride is a first-in-class selective, high affinity serotonin 5-hydroxytryptamine type 4 (5-HT4) receptor agonist promoting gastro-intestinal prokinetic activity and has been evaluated for the treatment of CC., Areas Covered: A PubMed search (1965 - 2014) using the following terms alone or in combination: prucalopride, 5-HT4, R093877, safety, toxicity, pharmacokinetics, pharmacodynamics, transit, cardiac, human ether-a-go-go related gene (hERG), arrhythmia, potassium current, elderly, children., Expert Opinion: Prucalopride, a highly selective 5-HT4 receptor agonist, stimulates gastrointestinal motility and has been proven to be effective in the treatment of CC in adults by increasing stool frequency, reducing constipation-related symptoms and improving quality of life (QoL). The safety and tolerability have been proven to be excellent. More research would be preferable on the effect of prucalopride on men, children and in other gastrointestinal motility disorders.

Background: Approximately, 20-30% of patients with gastro-esophageal reflux disease (GERD) experience persistent symptoms despite treatment with proton pump inhibitors (PPIs). These patients may have underlying dysmotility; therefore, targeting gastric motor dysfunction in addition to acid inhibition may represent a new therapeutic avenue. The aim of this study was to assess the pharmacodynamic effect of the prokinetic agent revexepride (a 5-HT4 receptor agonist) in patients with GERD who have persistent symptoms despite treatment with a PPI., Methods: This was a phase II, exploratory, multicenter, randomized, placebo-controlled, double-blind, parallel-group study in patients with GERD who experienced persistent symptoms while taking a stable dose of PPIs (ClinicalTrials.gov identifier: NCT01370863). Patients were randomized to either revexepride (0.5 mg, three times daily) or matching placebo for 4 weeks. Reflux events and associated characteristics were assessed by pH/impedance monitoring and disease symptoms were assessed using electronic diaries and questionnaires., Key Results: In total, 67 patients were enrolled in the study. There were no significant differences between study arms in the number, the mean proximal extent or the bolus clearance times of liquid-containing reflux events. Changes from baseline in the number of heartburn, regurgitation, and other symptom events were minimal for each treatment group and no clear trends were observed., Conclusions & Inferences: No clear differences were seen in reflux parameters between the placebo and revexepride groups., (© 2014 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Introduction: Parkinson's disease (PD) affects the nerves of the entire gastrointestinal (GI) tract and may result in profound gastrointestinal (GI) dysfunction leading to poor patient outcomes. Common GI disturbances in patients with PD include gastroparesis (GP), constipation and small intestinal bacterial overgrowth syndrome (SIBO). In particular, GP is difficult to treat due to the limited options available and precautions, contraindications and adverse effects associated with the approved treatments. Moreover, some commonly used medications can worsen pre-existing PD., Areas Covered: Our review will focus on treatment options for GP and SIBO with motilin agonists, dopamine receptor antagonists, Ghrelin agonists muscarinic agonists, 5-HT4 receptor agonists, antibiotics, probiotics and herbal formulation such as iberogast. Constipation occurs in the majority of patients with PD and fortunately many treatments are now available. Our review is based on original papers or reviews selected from PUBMED search and Cochrane reviews., Expert Opinion: Motility disorders of the GI tract are found frequently in patients with PD and treating the underlying GI disorders caused by PD with various prokinetics and laxatives is paramount in achieving improvements in patient's motor function. Various prokinetics and laxatives are now available to provide some relief of the GI morbidity caused by PD leading even to better absorption of even the PD treatments.