Roberts M C, Argenzio A
Equine Vet J. 1986 Jul;18(4):256-60. doi: 10.1111/j.2042-3306.1986.tb03620.x.
Amitraz, atropine, glycopyrrolate and morphine (but not its derivatives, meperidine [pethidine], oxymorphone and butorphanol) produced similar effects on clinically observed intestinal functions and significantly prolonged intestinal transit, as assessed with polyethylene glycol (PEG). However, their mechanisms of action, particularly on intestinal transport (fluid movement), may differ widely. Loperamide appeared to exert a preferential action on intestinal transport rather than motility, as there was no significant delay in PEG transit. The action of amitraz in perturbing smooth muscle coordination and enhancing absorption involved, at least partially, an alpha 2 adrenergic component susceptible to yohimbine. Naloxone, an opiate antagonist, did not influence amitraz responses but induced the return of intestinal sounds and defecation after a refractory period in morphine-dosed ponies. The results suggest potential clinical applications in horses for loperamide in diarrhoea therapy, for alpha 2 adrenergic antagonists in obstruction and ileus and, possibly, of amitraz-like agents in reducing fluid losses in diarrhoea.
阿米特拉嗪、阿托品、格隆溴铵和吗啡（但不包括其衍生物哌替啶、羟吗啡酮和布托啡诺）对临床观察到的肠道功能产生了类似的影响，并显著延长了肠道转运时间，这是通过聚乙二醇（PEG）评估得出的。然而，它们的作用机制，特别是对肠道转运（液体移动）的作用机制，可能有很大差异。洛哌丁胺似乎对肠道转运而非蠕动具有优先作用，因为PEG转运没有明显延迟。阿米特拉嗪在扰乱平滑肌协调性和增强吸收方面的作用，至少部分涉及对育亨宾敏感的α2肾上腺素能成分。阿片拮抗剂纳洛酮不影响阿米特拉嗪的反应，但在给吗啡的小马经过一段不应期后，可促使肠道声音恢复和排便。结果表明，洛哌丁胺在马腹泻治疗中、α2肾上腺素能拮抗剂在肠梗阻和肠麻痹治疗中以及可能的阿米特拉嗪类药物在减少腹泻时的液体流失方面具有潜在的临床应用价值。
