Rivera L, Hernández M, Benedito S, Prieto D, García-Sacristán A
Departamento de Fisiología, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Res Vet Sci. 1992 Jan;52(1):57-61. doi: 10.1016/0034-5288(92)90058-a.
The effects of alpha- and beta-adrenoceptor agonists and antagonists were studied in the sheep ureterovesical junction. Non-specific adrenergic agonists such as adrenaline and noradrenaline induced contraction in the sheep ureterovesical junction, suggesting a predominance of alpha-over beta-adrenoceptors in this functional unity. An inhibition of the noradrenaline-induced contraction was observed after prior blocking with prazosin (10(-7) M) and yohimbine (10(-7) M), the effect of prazosin being more potent than that of yohimbine. The effect of phenylephrine on alpha 1-adrenoceptors was more potent than that of B-HT 920 on alpha 2-adrenoceptors. Isoproterenol caused a concentration-dependent relaxation that was inhibited by propranolol (10(-6) M), pafenolol (10(-5) M) and butoxamine (10(-5) M). These results suggest that ureterovesical junction contraction is mediated by both alpha 1 and alpha 2-adrenoceptors, alpha 1 predominating over alpha 2. Relaxation is mediated by beta-adrenoceptors of the beta 1 and beta 2 subtypes.
在绵羊输尿管膀胱连接处研究了α和β肾上腺素能受体激动剂及拮抗剂的作用。非特异性肾上腺素能激动剂如肾上腺素和去甲肾上腺素可引起绵羊输尿管膀胱连接处收缩，提示在这个功能单位中α肾上腺素能受体比β肾上腺素能受体占优势。在用哌唑嗪（10⁻⁷M）和育亨宾（10⁻⁷M）预先阻断后，观察到去甲肾上腺素诱导的收缩受到抑制，哌唑嗪的作用比育亨宾更强。苯肾上腺素对α1肾上腺素能受体的作用比B-HT 920对α2肾上腺素能受体的作用更强。异丙肾上腺素引起浓度依赖性舒张，该舒张被普萘洛尔（10⁻⁶M）、帕非洛尔（10⁻⁵M）和丁氧胺（10⁻⁵M）抑制。这些结果表明，输尿管膀胱连接处收缩由α1和α2肾上腺素能受体介导，α1比α2占优势。舒张由β1和β2亚型的β肾上腺素能受体介导。
