Motility of the equine gastrointestinal tract: Physiology and pharmacotherapy

Abstract

Summary Normal gastrointestinal (GI) motility patterns are necessary to maintain transit of ingesta and to facilitate digestion and absorption of nutrients. Disorders of the equine GI tract are frequently encountered by the equine practitioner and these disorders are often associated with an interruption in normal intestinal motility patterns, thus complicating treatment of the primary disease. Consequently, numerous treatments have been investigated in horses to facilitate the return of normal intestinal motility. The purpose of this article is to provide a brief review of the anatomy and physiology of the GI tract in the horse and review medications available to the equine veterinarian that may potentially promote intestinal motility.

An update on equine post‐operative ileus: Definitions, pathophysiology and management

“…The most commonly used prokinetics in equine POI management are lidocaine (lignocaine), metoclopramide, erythromycin lactobionate and neostigmine [8,9,145], and their use and efficacy have been much debated in the human and equine clinical literature. The reader is directed to a review of Wong et al (2011) for a comprehensive overview of the clinical indications for the use of various prokinetic drug classes in the horse, including their modes of action and suggested dosing regimens [146]. While there are several studies supporting the use of lidocaine in the management of equine POI [35,118], a recent review failed to identify any beneficial effects of its use [147].…”

Current Strategies for Prevention and Treatment of Equine Postoperative Ileus: A Multimodal Approach

“…These results suggest that the drug would not be appropriate for gastric and small intestinal problems but may be beneficial for large intestinal motility dysfunction. However, neostigmine increased the amplitude of rhythmic contractions in both the resting and distended jejunum in anesthetized ponies, and it induced contractile activity in the ileum, supporting its use for motility dysfunction in both the small and large intestine [26,29,124]. Based on our clinical impressions, neostigmine if used as monotherapy repeated at 60 min intervals (during 24-48 h) has significant beneficial effects in the treatment of colitis cases, but not in POI of the small intestine [43].…”

“…The enteric nervous system influences the gastrointestinal tract either directly through neurotransmitters or indirectly through intermediate cells, such as the ICC, cells of the immune system or endocrine cells [10]. These intestinal neurons communicate through more than 25 different neurotransmitters, including stimulatory neurotransmitters (acetylcholine, neurokinin A, adenosine, substance P, motilin, serotonin and cholecystokinin) and inhibitory neurotransmitters, for instance, vasoactive intestinal peptide (VIP), nitrous oxide (NO), neuropeptide Y, calcitonin gene-related peptide, GABA and neurotensin [26][27][28][29].The endocrine system also indirectly affects regulation of the gastrointestinal tract motility. The hormones related to stress activity (glucocorticoids, cortico-realizing peptide, thyroid hormones and somatotropic hormone) have the most pronounced inhibitory effect on gastrointestinal tract activity.…”

Efeito da eletroacupuntura sobre a motilidade e trânsito intestinal de equinos

“…A progressão da digesta ocorre devido à motilidade gastrointestinal, que é dependente de fatores nervosos, físicos, químicos e celulares (WONG; DAVIS; WHITE, 2011). Esta dependência é melhor compreendida quando se observa a característica estrutural do intestino equino, que apresenta cinco camadas teciduais, ou seja, mucosa, submucosa, fibras musculares circulares, fibras musculares longitudinais e serosa (WONG; DAVIS; WHITE, 2011), onde está localizada a inervação intestinal, definida como sistema nervoso entérico (SNE) (GRUNDY; SCHEMANN, 2005).…”

“…As causas exatas dos eventos que ocorrem para que se desenvolva o ileus nos equinos ainda não estão totalmente esclarecidas, muito do que se propõe advém dos conhecimentos em humanos (DELESALLE et al, 2006;PIRIE, 2015;WONG;DAVIS;WHITE, 2011). Porém, sabe-se que esta condição está relacionada ao uso de alguns fármacos tais como anestésicos e opioides, presença de úlceras gastrointestinais, obstruções intraluminais, distensões excessivas de parede intestinal, obstruções estrangulativas, peritonite, síndrome da resposta inflamatória sistêmica (SIRS), exaustão, desordens inflamatórias, desordens metabólicas e, a causa mais comum delas e que engloba vários dos fatores citados, em consequência de laparotomias devido ao abdomen agudo, conhecido como ileus pós operatório (Postoperative ileus -POI) (ADAMS, 1988;LISOWSKI et al, 2018;SANCHEZ, 2010).…”