Fox A W, Friedman P A
J Pharm Pharmacol. 1987 Jan;39(1):68-71. doi: 10.1111/j.2042-7158.1987.tb07169.x.
The accumulation of inositol phosphates (IP) in smooth muscle from rat vas deferens and caudal artery was maximally increased 3- to 4-fold in response to exposure of the tissues to 100 microM noradrenaline. Clonidine (up to 3 mM) was a partial agonist. Pretreatment of the tissues with the irreversible alpha-adrenoceptor antagonist phenoxybenzamine (0.3-10 microM) shifted the noradrenaline concentration-response curve to the right before depressing the maximum. The maximum of the clonidine concentration-response curve was depressed without significant change in the EC50 by the same treatment. These data, which are most easily interpreted as demonstrating the presence of a receptor reserve for IP accumulation, are discussed.
将大鼠输精管和尾动脉的平滑肌组织暴露于100微摩尔去甲肾上腺素后，肌醇磷酸（IP）的积累量最大可增加3至4倍。可乐定（浓度高达3毫摩尔）是一种部分激动剂。用不可逆的α-肾上腺素能受体拮抗剂酚苄明（0.3至10微摩尔）对组织进行预处理，可使去甲肾上腺素浓度-反应曲线右移，然后才降低其最大值。相同处理使可乐定浓度-反应曲线的最大值降低，但半数有效浓度（EC50）无显著变化。对这些数据进行了讨论，这些数据最容易被解释为表明存在用于IP积累的受体储备。
