Brikas P
Laboratory of Physiology, Veterinary Faculty, Aristotelian University, Thessaloniki, Greece.
J Vet Pharmacol Ther. 1989 Sep;12(3):261-6. doi: 10.1111/j.1365-2885.1989.tb00669.x.
In five conscious adult ewes at rest, chronically implanted with electrodes in the musculature of the omasal wall, intravenous (i.v.) infusion for 30 min of alpha 1- or alpha 2-adrenergic receptor blockers, prazosin (20 micrograms/kg/min) and yohimbine (30 micrograms/kg/min), respectively, had no significant effects on omasal myoelectrical activity. The i.v. administration for 15 min of alpha 1- or alpha 2-agonists phenylephrine (4 micrograms/kg/min) or naphazoline (2.5 micrograms/kg/min), respectively, increased the frequency and the amplitude of groups of myoelectrical discharges of omasum, as well as the duration of its activity. Pretreatment of animals with prazosin blocked the responses to phenylephrine. Yohimbine prevented the effects of naphazoline dose-dependently. It is suggested that both alpha 1- and alpha 2-adrenoreceptors are involved in regulation of the sheep's omasal notility. This regulation did not seem to be a simple consequence of the changes in the reticular motility.
在五只清醒的成年母羊休息时，将电极长期植入其瓣胃壁肌肉组织中，分别静脉输注（i.v.）α1或α2肾上腺素能受体阻滞剂哌唑嗪（20微克/千克/分钟）和育亨宾（30微克/千克/分钟）30分钟，对瓣胃肌电活动无显著影响。分别静脉注射α1或α2激动剂去氧肾上腺素（4微克/千克/分钟）或萘甲唑啉（2.5微克/千克/分钟）15分钟，可增加瓣胃肌电放电组的频率和幅度以及其活动持续时间。用哌唑嗪预处理动物可阻断对去氧肾上腺素的反应。育亨宾可剂量依赖性地阻止萘甲唑啉的作用。提示α1和α2肾上腺素能受体均参与绵羊瓣胃动力的调节。这种调节似乎并非网胃动力变化的简单结果。
