哌唑嗪和酚妥拉明对大鼠输精管和肛尾肌对场刺激及去甲肾上腺素反应的影响。

Effects of prazosin and phentolamine on responses to field stimulation and to noradrenaline in vas deferens and anococcygeus muscle of the rat.

作者信息

Doggrell S A, Paton D M

出版信息

Arch Int Pharmacodyn Ther. 1978 Jun;233(2):209-20.

Abstract

The effects of phentolamine (10(-6)M) and prazosin (10(-7)M) on contractile responses, in the presence of cocaine or nortriptyline, were investigated in vas deferens and anococcygeus muscle of rat. Cocaine (10(-5)M) and nortriptyline (10(-6)M) had no effect on maximum responses to field stimulation, (--)-noradrenaline, methoxamine, and acetylcholine in anococcygeus muscle. However, both cocaine (3.3 x 10(-5)M) and nortripthline (10(-6)M) potentiated maximum responses to (--)-noradrenaline without altering the maximum response to field stimulation in vas deferens. In vas deferens, phentolamine potentiated or inhibited the responses to field stimulation depending on the frequency whereas prazosin inhibited all responses to field stimulation. In anococcygeus muscle, both phentolamine and prazosin inhibited all responses to field stimulation. In vas deferens and anococcygeus muscle, prazosin was a more potent antagonist of responses to (--)-noradrenaline than phentolamine. These results show that prazosin is a more potent postsynaptic alpha-adrenoceptor antagonist than phentolamine and suggest that prazosin has little or no affinity for presynaptic alpha-adrenoceptors.

摘要

在大鼠的输精管和肛门尾骨肌中，研究了酚妥拉明（10⁻⁶M）和哌唑嗪（10⁻⁷M）在可卡因或去甲替林存在时对收缩反应的影响。可卡因（10⁻⁵M）和去甲替林（10⁻⁶M）对肛门尾骨肌对场刺激、（-）-去甲肾上腺素、甲氧明和乙酰胆碱的最大反应无影响。然而，可卡因（3.3×10⁻⁵M）和去甲替林（10⁻⁶M）均增强了输精管对（-）-去甲肾上腺素的最大反应，而不改变对场刺激的最大反应。在输精管中，酚妥拉明根据频率增强或抑制对场刺激的反应，而哌唑嗪抑制对场刺激的所有反应。在肛门尾骨肌中，酚妥拉明和哌唑嗪均抑制对场刺激的所有反应。在输精管和肛门尾骨肌中，哌唑嗪是比酚妥拉明更有效的对（-）-去甲肾上腺素反应的拮抗剂。这些结果表明，哌唑嗪是比酚妥拉明更有效的突触后α-肾上腺素能受体拮抗剂，并提示哌唑嗪对突触前α-肾上腺素能受体几乎没有或没有亲和力。