Effect of enterokinetic prucalopride on intestinal motility in fast rats

Relationship Between Intestinal Slow-waves, Spike-bursts, and Motility, as Defined Through High-resolution Electrical and Video Mapping

Background/Aims

High-resolution extracellular mapping has improved our understanding of bioelectric slow-wave and spike-burst activity in the small intestine. The spatiotemporal correlation of electrophysiology and motility patterns is of critical interest to intestinal function but remains incompletely defined.

Methods

Intestinal jejunum segments from in vivo pigs and rabbits were exteriorized, and simultaneous high-resolution extracellular recordings and video recordings were performed. Contractions were quantified with strain fields, and the frequencies and velocities of motility patterns were calculated. The amplitudes, frequencies, and velocities of slow-wave propagation patterns and spike-bursts were quantified and visualized. In addition, the duration, size and energy of spike-burst patches were quantified.

Results

Slow-wave associated spike-bursts activated periodically at 10.8 ± 4.0 cycles per minute (cpm) in pigs and 10.2 ± 3.2 cpm in rabbits, while independent spike-bursts activated at a frequency of 3.2 ± 1.8 cpm. Independent spike-bursts had higher amplitude and longer duration than slow-wave associated spike-bursts (1.4 ± 0.8 mV vs 0.1 ± 0.1 mV, P < 0.001; 1.8 ± 1.4 seconds vs 0.8 ± 0.3 seconds, P < 0.001 in pigs). Spike-bursts that activated as longitudinal or circumferential patches were associated with contractions in the respective directions. Spontaneous peristaltic contractions were elicited by independent spike-bursts and travelled slower than slow-wave velocity (3.7 ± 0.5 mm/sec vs 10.1 ± 4.7 mm/sec, P = 0.007). Cyclic peristaltic contractions were driven by slow-wave associated spike-bursts and were coupled to slow-wave velocity and frequency in rabbit (14.2 ± 2.3 mm/sec vs 11.5 ± 4.6 mm/sec, P = 0.162; 11.0 ± 0.6 cpm vs 10.8 ± 0.6 cpm, P = 0.970).

Conclusions

Motility patterns were dictated by patterns of spike-burst patches. When spike-bursts were coupled to slow-waves, periodic motility patterns were observed, while when spike-bursts were not coupled to slow-waves, spontaneous aperiodic motility patterns were captured.

Preclinical experimental models for assessing laxative activities of substances/products under investigation: a scoping review of the literature

Constipation is a common gastrointestinal problem worldwide. Its impact on health can range from an unpleasant problem to being seriously troublesome. When lifestyle modification fails to deal with constipation, laxatives are the mainstay of therapy. There are several types of laxatives currently available; however, there still remains a need for better laxatives because certain currently available laxatives are not appropriate for or accessible to some patients. Preclinical experiments to study the laxative potential of substances/products of interest are vital to improving that situation. The selection of appropriate experimental models for assessing the laxative activities of substances/products under investigation is crucial to achieving valid and meaningful results. This article provides a scoping review of the literature, outlining, and summarizing models currently being used in preclinical experiments assessing the laxative activities of substances/products under investigation. The review includes both screening models, e.g., the isolated organ bath system, in vivo fecal assessment and intestinal transit assay, and confirmation models, e.g., in vivo constipation models. Chemical substances/drugs used to induce constipation in in vivo constipation models, e.g., loperamide, diphenoxylate, montmorillonite, and clonidine, as well as standard laxative agents used as a positive control in experimental models, e.g., bisacodyl, carbachol, lactulose, sodium picosulfate, castor oil, phenolphthalein, and yohimbine, are described in detail. The purpose of this article is to assist researchers in the design and implementation of preclinical experimental models for assessing laxative activities of substances/products under investigation to achieve valid and meaningful preclinical results prior to experimentation in humans.

Effects and sites of action of a M1 receptor positive allosteric modulator on colonic motility in rats and dogs compared with 5-HT4 agonism and cholinesterase inhibition

BACKGROUND

Muscarinic receptor 1 positive allosteric modulators (M1PAMs) enhance colonic propulsive contractions and defecation through the facilitation of M1 receptor (M1R)-mediated signaling. We examined M1R expression in the colons of 5 species and compared colonic propulsion and defecation caused by the M1PAM, T440, the 5-HT₄ agonist, prucalopride, and the cholinesterase inhibitor, neostigmine, in rats and dogs.

METHODS

M1R expression was profiled by immunostaining and in situ hybridization. In vivo studies utilized male SD rats and beagle dogs. Colonic propulsive contractions were recorded by manometry in anesthetized rats. Gut contractions in dogs were assessed using implanted force transducers in the ileum, proximal, mid, and distal colons.

KEY RESULTS

M1R was localized to neurons of myenteric and submucosal plexuses and the epithelium of the human colon. A similar receptor localization was observed in rat, dog, mouse, and pig. T440 enhanced normal defecation in rats in a dose-dependent manner. Prucalopride also enhanced defecation in rats, but the maximum effect was half that of T440. Neostigmine and T440 were similarly effective in enhancing defecation, but the effective dose of neostigmine was close to its lethal dose. In rats, all 3 compounds induced colonic contractions, but the associated propulsion was strongest with T440. In dogs, intestinal contractions elicited by T440 propagated from ileum to distal colon. Prucalopride and neostigmine also induced intestinal contractions, but these were less well coordinated. No loss of effectiveness of T440 on defecation occurred after 5 days of repeated dosing.

CONCLUSION AND INFERENCES

These results suggest that M1PAMs produce highly coordinated propagating contraction by actions on the enteric nervous system of the colon. The localization of M1R to enteric neurons in both animals and humans suggests that the M1PAM effects would be translatable to human. M1PAMs provide a potential novel therapeutic option for constipation disorders.

YH12852, a potent and highly selective 5-HT4 receptor agonist, significantly improves both upper and lower gastrointestinal motility in a guinea pig model of postoperative ileus

BACKGROUND

Postoperative ileus (POI) is a transient gastrointestinal (GI) dysmotility that commonly develops after abdominal surgery. YH12852, a novel, potent and highly selective 5-hydroxytryptamine 4 (5-HT₄ ) receptor agonist, has been shown to improve both upper and lower GI motility in various animal studies and may have applications for the treatment of POI. Here, we investigated the effects and mechanism of action of YH12852 in a guinea pig model of POI to explore its therapeutic potential.

METHODS

The guinea pig model of POI was created by laparotomy, evisceration, and gentle manipulation of the cecum for 60 seconds, followed by closure with sutures under anesthesia. Group 1 received an oral administration of vehicle or YH12852 (1, 3, 10 or 30 mg/kg) only, while POI Group 2 was intraperitoneally pretreated with vehicle or 5-HT₄ receptor antagonist GR113808 (10 mg/kg) prior to oral dosing of vehicle or YH12852 (3 or 10 mg/kg). Upper GI transit was evaluated by assessing the migration of a charcoal mixture in the small intestine, while lower GI transit was assessed via measurement of fecal pellet output (FPO).

KEY RESULTS

YH12852 significantly accelerated upper and lower GI transit at the doses of 3, 10, and 30 mg/kg and reached its maximal effect at 10 mg/kg. These effects were significantly blocked by pretreatment of GR113808 10 mg/kg.

CONCLUSION AND INFERENCES

Oral administration of YH12852 significantly accelerates and restores delayed upper and lower GI transit in a guinea pig model of POI. This drug may serve as a useful candidate for the treatment of postoperative ileus.

Tracking gastrointestinal transit of solids in aged rats as pharmacological models of chronic dysmotility

BACKGROUND

Dysmotility in the gastrointestinal (GI) tract often leads to impaired transit of luminal contents leading to symptoms of diarrhea or constipation. The aim of this research was to develop a technique using high resolution X-ray imaging to study pharmacologically induced aged rat models of chronic GI dysmotility that mimic accelerated transit (diarrhea) or constipation. The 5-hydroxytryptamine type 4 (5-HT4 ) receptor agonist prucalopride was used to accelerate transit, and the opioid agonist loperamide was used to delay transit.

METHODS

Male rats (18 months) were given 0, 1, 2, or 4 mg/kg/day prucalopride or loperamide (in dimethyl sulfoxide, DMSO) for 7 days by continuous 7-day dosing. To determine the GI region-specific effect, transit of six metallic beads was tracked over 12 h using high resolution X-ray imaging. An established rating scale was used to classify GI bead location in vivo and the distance beads had propagated from the caecum was confirmed postmortem.

KEY RESULTS

Loperamide (1 mg/kg) slowed stomach emptying and GI transit at 9 and 12 h. Prucalopride (4 mg/kg) did not significantly alter GI transit scores, but at a dose of 4 mg/kg beads had moved significantly more distal than the caecum in 12 h compared to controls.

CONCLUSIONS & INFERENCES

We report a novel high-resolution, non-invasive, X-ray imaging technique that provides new insights into GI transit rates in live rats. The results demonstrate that loperamide slowed overall transit in aged rats, while prucalopride increased stomach emptying and accelerates colonic transit.

Efficacy and safety of prucalopride in adults and children with chronic constipation

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.

The effects of prucalopride on postoperative ileus in guinea pigs

PURPOSE

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 hospitalization. The aim of this study was to investigate the effects of different 5-hydroxytryptamine 4 (5-HT₄) receptor agonists, which stimulate excitatory pathways, on a POI model.

MATERIALS AND METHODS

The experimental model of POI in guinea pigs was created by laparotomy, gentle manipulation of the cecum for 60 seconds, and closure by suture, all under anesthesia. Different degrees of restoration of GI transit were measured by the migration of charcoal. Colonic transit was indirectly assessed via measurement of fecal pellet output every hour for 5 hours after administration of various doses of mosapride, tegaserod, prucalopride, and 5-HT.

RESULTS

Charcoal transit assay showed that various 5-HT₄ receptor agonists can accelerate delayed upper GI transit in a dose-dependent manner. However, fecal pellet output assay suggested that only prucalopride had a significant effect in accelerating colonic motility in POI.

CONCLUSION

Although mosapride, tegaserod, and prucalopride produce beneficial effects to hasten upper GI transit in the POI model, prucalopride administered orally restores lower GI transit as well as upper GI transit after operation in a conscious guinea pig. This drug may serve as a useful candidate for examination in a clinical trial for POI.

Prucalopride: evaluation of the pharmacokinetics, pharmacodynamics, efficacy and safety in the treatment of chronic constipation

INTRODUCTION

Prucalopride is the first member of a novel class of 5-HT(4) receptor agonist which has been extensively evaluated for the treatment of chronic constipation. Predominantly, prucalopride is currently used to treat patients that show an insufficient response to laxatives as an alternative form of therapy.

AREAS COVERED

The following article provides the reader with a systematic review of the literature on prucalopride. Specifically, the article reviews the currently literature on the pharmacokinetics and the pharmacodynamics of the drugs as well as reviewing literature on its efficacy. Furthermore, the authors also highlight the safety and tolerability of the drug that have been demonstrated in its clinical development.

EXPERT OPINION

Prucalopride is an important addition to the therapeutic abilities for treating chronic constipation, especially in females poorly responding to laxatives. The safety profile of the drug, to date, is favorable. There is also the possibility that prucalopride might be of benefit to other disorders of gastrointestinal motility with a number of studies currently in progress, which are evaluating alternative applications.

Trichosanthes dioica root possesses stimulant laxative activity in mice

Trichosanthes dioica Roxb. (Cucurbitaceae), named 'pointed gourd' in English, is a dioecious climber grown in India. This study was aimed at evaluating the laxative activity of the aqueous extract of T. dioica root (TDA) in Swiss albino mice. The laxative activity of TDA (100 and 200 mg kg(-1) body weight per os) was evaluated by assessing the excretory bowel activities in naive (non-constipated) and in drug (loperamide)-induced constipation in mice. Further, the gastrointestinal transit was measured in both naive and in constipated mice. Castor oil (0.5 mL/mouse per os) was used as the reference. TDA significantly and dose-dependently increased all the excretory bowel activities and gastrointestinal transit in both naive and constipated mice. TDA at 200 mg kg(-1) body weight was found to be the most active, causing diarrhoea in mice. Thus, T. dioica root demonstrated stimulant laxative activity in Swiss mice, validating its traditional usage in India.

Role of prucalopride, a serotonin (5-HT(4)) receptor agonist, for the treatment of chronic constipation

Constipation affects up to a quarter of the population in developed countries and is associated with poor quality of life and significant economic burden. Many patients with chronic constipation are dissatisfied with current therapy due to lack of long-term efficacy or side effects. Previous nonselective 5-hydroxytryptamine receptor 4 (5-HT₄) agonists have been associated with significant interactions with other receptors (5-HT_1B, 5-HT_1D, and 5-HT_2B for tegaserod; hERG for cisapride), leading to adverse cardiovascular events resulting in withdrawal of these drugs from the market. Prucalopride is a novel gastrointestinal prokinetic agent. It acts as a high affinity, highly-selective 5-HT₄ agonist. Its efficacy in patients with chronic constipation has been demonstrated in several phase II and phase III clinical trials showing significant improvements in bowel transit, bowel function, gastrointestinal symptoms, and quality of life, with benefit maintained for up to 24 months in open label, multicenter, follow-up studies. Prucalopride’s high selectivity for the 5-HT₄ receptor may explain its favorable safety and tolerability profiles, even in elderly subjects with stable cardiovascular disease. Prucalopride is a well tolerated and efficacious prokinetic medication that should enhance the treatment of chronic constipation unresponsive to first-line treatments.

Prucalopride: a new drug for the treatment of chronic constipation

Prucalopride belongs to a novel class of 5-hydroxytryptamine-4 receptor agonists, and has been evaluated extensively for the treatment of chronic constipation. Prucalopride has a stimulatory effect on gastrointestinal motility and transit, as established by in vivo and in vitro studies in animals and humans. Its therapeutic efficacy, tolerability and safety have been evaluated in Phase II and Phase III studies in chronic constipation. The cardiovascular safety profile of the drug was studied in vitro and in vivo in animal studies, in clinical studies in chronic constipation patients, as well as in specific additional clinical cardiovascular studies. Phase II studies identified a dose-dependent effect of prucalopride on bowel pattern and associated symptoms in chronic constipation. The Phase III studies mainly recruited patients with insufficient response to laxatives, and showed consistent efficacy and excellent tolerability for prucalopride.

5-HT4 receptor agonists increase sAPPalpha levels in the cortex and hippocampus of male C57BL/6j mice

BACKGROUND AND PURPOSE

A strategy to treat Alzheimer's disease (AD) is to increase the soluble form of amyloid precursor protein (sAPPalpha), a promnesic protein, in the brain. Because strong evidence supports beneficial effects of 5-hydroxytryptamine 5-HT(4) receptor agonists in memory and learning, we investigated the role of 5-HT(4) receptors on APP processing in 8 weeks-old male C57BL/6j mice.

EXPERIMENTAL APPROACH

Mice were given, subcutaneously, prucalopride or ML 10302 (s.c.), two highly selective 5-HT(4) receptor agonists and, up to 240 min later, the hippocampus and cortex were analysed by Western blot for sAPPalpha determination.

KEY RESULTS

Prucalopride (5 or 10 mg kg(-1)) significantly increased sAPPalpha levels in the hippocampus and cortex, but did not modify the expression level of APP mRNA as detected by quantitative RT-PCR. A selective 5-HT(4) receptor antagonist, GR125487 (1 mg kg(-1), s.c.) inhibited prucalopride induced- increase in sAPPalpha levels. In addition, levels of sAPPalpha were increased by ML10302 only at 20 mg kg(-1) and was limited to the cortex. Also, prucalopride increased sAPPalpha levels in the cortex of a transgenic mouse model of AD, expressing the London mutation of APP. Furthermore, the combined injection of a selective acetylcholinesterase inhibitor, donepezil and prucalopride induced a synergic increase in sAPPalpha levels in the cortex and hippocampus.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrate that the 5-HT(4) receptor plays a key role in the non-amyloidogenic pathway of APP metabolism in vivo and give support to the beneficial use of 5-HT(4) agonists for AD treatment.