Breuiller-Fouche M, Doualla-Bell Kotto Maka F, Geny B, Ferre F
INSERM U.166 Groupe de recherches sur l'Endocrinologie de la Reproduction, Maternité Baudelocque, Paris, France.
J Pharmacol Exp Ther. 1991 Jul 1;258(1):82-7.
Alpha-1 adrenergic receptors were examined in both inner and outer layers of human pregnant myometrium using radioligand binding of [3H]prazosin. [3H]prazosin bound rapidly and reversibly to a single class of high affinity binding sites in myometrial membrane preparations. Scatchard analysis gave similar values of equilibrium dissociation constants in both myometrial layers. In contrast, more alpha-1 adrenergic receptors were detected in the outer layer than in the inner layer. Antagonist inhibited [3H]prazosin binding with an order of potency of prazosin greater than phentolamine greater than idazoxan. Competition experiments have also revealed that a stable guanine nucleotide decreases the apparent affinity of norepinephrine for myometrial [3H]prazosin binding sites. The functional status of these alpha-1 adrenergic receptors was also assessed by measuring the norepinephrine-induced accumulation of inositol phosphates in myometrial tissue. Norepinephrine produced a concentration-dependent accumulation of inositol phosphates in both myometrial layers. However, norepinephrine-induced increases in inositol 1,4,5-triphosphate were only observed in the outer layer. These results indicate that alpha-1 adrenergic receptors in human myometrium at the end of pregnancy are linked to phosphoinositide hydrolysis and that this response occurs mainly in the outer layer.
采用[3H]哌唑嗪放射性配体结合法，对人妊娠子宫肌层的内层和外层的α1肾上腺素能受体进行了检测。[3H]哌唑嗪能快速、可逆地结合到子宫肌层膜制剂中的一类单一高亲和力结合位点上。Scatchard分析显示，子宫肌层两层的平衡解离常数相似。然而，在外层检测到的α1肾上腺素能受体比内层更多。拮抗剂抑制[3H]哌唑嗪结合的效力顺序为：哌唑嗪大于酚妥拉明大于咪唑克生。竞争实验还表明，稳定的鸟嘌呤核苷酸会降低去甲肾上腺素对子宫肌层[3H]哌唑嗪结合位点的表观亲和力。还通过测量去甲肾上腺素诱导的子宫肌层组织中肌醇磷酸的积累来评估这些α1肾上腺素能受体的功能状态。去甲肾上腺素在子宫肌层两层均产生浓度依赖性的肌醇磷酸积累。然而，去甲肾上腺素诱导的肌醇1,4,5-三磷酸增加仅在外层观察到。这些结果表明，妊娠末期人子宫肌层中的α1肾上腺素能受体与磷酸肌醇水解有关，且这种反应主要发生在外层。
