Krulich L, Jurcovicová J, Le T
Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235-9040.
Life Sci. 1989;44(12):809-18. doi: 10.1016/0024-3205(89)90378-0.
The effects of the alpha 2 adrenergic receptor antagonists yohimbine (YOH) and Idazoxan (ID) on secretion of PRL were compared in nonanesthetized male rats bearing permanent intraatrial cannulae for i.v. drug delivery and serial blood sampling. YOH induced a dose-related elevation of basal plasma PRL levels. ID had either no effect or a tendency to lower them and effectively inhibited stimulation of PRL secretion with morphine, 5-hydroxytryptophan (5HTP), quipazine or restraint stress. YOH at low doses did not alter the PRL secretory responses to these stimuli or enhanced them at the highest dose used (1.56 mg/kg). ID inhibited the PRL-stimulating, effect of 5HTP or morphine following inhibition of NE synthesis with FLA63 or pretreatment with clonidine. It also blocked the effect of quipazine in rats pretreated with prazosin. It is concluded that ID, in a complete contrast to YOH effectively inhibits PRL secretion. The inhibitory mechanism appears to be unrelated to its interaction with the alpha adrenergic receptors.
在带有永久性心房插管用于静脉给药和连续采血的未麻醉雄性大鼠中，比较了α2肾上腺素能受体拮抗剂育亨宾（YOH）和咪唑克生（ID）对催乳素（PRL）分泌的影响。YOH可引起基础血浆PRL水平呈剂量相关的升高。ID要么无作用，要么有降低基础血浆PRL水平的趋势，并且可有效抑制吗啡、5-羟色氨酸（5HTP）、喹哌嗪或束缚应激对PRL分泌的刺激。低剂量的YOH不会改变对这些刺激的PRL分泌反应，或者在所用的最高剂量（1.56mg/kg）时增强这些反应。在用FLA63抑制去甲肾上腺素（NE）合成或用可乐定预处理后，ID可抑制5HTP或吗啡对PRL的刺激作用。它还可阻断喹哌嗪对用哌唑嗪预处理的大鼠的作用。得出的结论是，与YOH形成完全对比的是，ID可有效抑制PRL分泌。其抑制机制似乎与其与α肾上腺素能受体的相互作用无关。
