In vitro effects of 5-hydroxytryptamine and cisapride on the circular smooth muscle of the jejunum of horses

Abstract

Clinical Research Abstracts British Equine Veterinary Association Congress 2015 Foreword and Acknowledgements This supplement is devoted to the publication of abstracts from the 2015 Congress of The British Equine Veterinary Association. The quality of research at the Congress was, as in previous years, high, and the selection process was difficult. Despite the inclusion of a larger number of research communications than in previous years only two-thirds of those submitted could be accepted. This year's Congress committee utilised the selection process initiated last year by Professor Celia Marr in partnership with EVJ. Abstracts were reviewed and objectively graded by two peer reviewers and a member of the Congress Committee before being subjected to a final selection process overseen by the Congress Chair. Thereafter, abstracts had to satisfy the requirements of EVJ for publication in this supplement. Those authors who have had their work accepted should be proud of their achievement. Those who were unsuccessful are doubtless disappointed; however, they have the reassurance that the standard was high and the process was fair. deserve thanks and recognition for a year of hard work. Particular thanks also to all of the anonymous peer reviewers who receive no recognition but gave their time not only to grade the abstracts submitted but also to provide constructive feedback to their authors. The selection process adopted for BEVA Congress sets a standard for other meetings to follow. Given the increasing competition for acceptance of research communications at major international meetings, and the importance of achieving acceptance for those seeking to fulfil the requirements of specialist colleges, such a rigourous selection process seems only right. Reasons for performing study: There are limited data surrounding the efficacy of oviductal flushing in restoring fertility in mares with repeated returns to oestrus. Objectives: To determine the conception and foaling rates in mares treated by laparoscopic topical application of prostaglandin E2 (PGE2) to the oviduct(s) in mares: i) in the breeding season (January-May), pre-covering; ii) in the breeding season, post covering; and iii) out of the breeding season (June-December). Study design: Follow-up study. Methods: Analysis of electronic patient records (EPRs) identified 29 mares that underwent oviductal flushing via laparoscopic surgery between 1 January 2008 and 12 October 2014. One mare underwent the procedure twice; once in the breeding season (pre-covering) and once out of the breeding season. Follow-up data were collected via EPRs and from Weatherbys (www.bloodstockreports.co.uk). Results: The procedure was used in 27 Thoroughbreds, one Warmblood and one Hanoverian. Mean age at the time of the procedure was 13.1 years (range 6-22 years). Mean duration barren prior to the procedure was 1.9 years (range 49 days-5.6 years). The mean time post flushing to the first positive ultrasound scan was 31 days, with average time post flushing to foaling of 367.6 days. Of ...

Expression and function of 5-hydroxytryptamine 4 receptors in smooth muscle preparations from the duodenum, ileum, and pelvic flexure of horses without gastrointestinal tract disease

“…41 Possible pathways include the arachidonic acid pathway and activation of sensory dendrites in the lamina propria, which leads to a sensory reflex arc. Similarly, in another previous study, 49 desensitization of equine jejunal specimens did not occur as a result of cumulative administration of 5-HT. Interestingly, this effect of 5-HT was not evident in pelvic flexure specimens.…”

In vitroeffects of cisapride, metoclopramide and bethanechol on smooth muscle preparations from abomasal antrum and duodenum of dairy cows

“…Comparing the in vitro results obtained from specimens from cattle with those from horses, dissimilarities between species are obvious: in the equine jejunum, MET increased the contractile activity of the circular layers (Nieto et al. , 2000b) and CIS induced a concentration‐dependent increase in the amplitude of contractions (Nieto et al. , 2000a).…”

“…It increases the release of acetylcholine from postganglionic nerve endings of the myenteric plexus in the gut and may also antagonize the inhibitory action of 5‐hydroxytryptamine (5‐HT) on the myenteric plexus (Dowling, 1995). In horses, CIS induced a concentration‐dependent increase in the contractile amplitude of smooth muscle preparations of the jejunum in vitro (Nieto et al. , 2000a).…”

Expression and function of 5-HT7 receptors in smooth muscle preparations from equine duodenum, ileum, and pelvic flexure

“…Among 5-HT receptors, 5-HT 3 , an ionotropic receptor, forming an ion channel pore that is opened or closed in the direct response to 5-HT, and 5-HT 4 , a metabotropic receptor, which is indirectly linked with ion-channels through G proteins, have been most extensively studied in gastroenterology. Drugs targeting 5-HT receptors have proven effective to modulate in vitro GI motility of many species including humans (Gershon, 2004), dogs, guinea-pigs (Grider et al, 1998; Tonini et al, 2005), rats (Grider et al, 1998), cats (Washabau and Sammarco, 1996) and horses (Delesalle et al, 2006; Nieto et al, 2000; Weiss et al, 2002). Seven families of serotonin receptors, designated 5-HT 1 to 5-HT 7 (Hoyer et al, 2002), are currently recognized and subtypes have been described for several of them.…”