DEVELOPMENT OF TOLERANCE TO THE PROLACTIN-RELEASING ACTION OF MORPHINE AND ITS MODULATION BY HYPOTHALAMIC DOPAMINE
DEVELOPMENT OF TOLERANCE TO THE PROLACTIN-RELEASING ACTION OF MORPHINE AND ITS MODULATION BY HYPOTHALAMIC DOPAMINE
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DOI：
10.1210/endo-106-5-1469
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发表时间：
1980-01-01
期刊：
影响因子：
4.8
通讯作者：
FANG, VS
中科院分区：
文献类型：
--
作者：
DEYO, SN;SWIFT, RM;FANG, VS
外源性和内源性阿片类药物刺激垂体前叶释放 PRL [催乳素]。吗啡和阿片肽[D-Ala2、D-Leu5]脑啡肽和β-内啡肽减少正中隆起神经末梢的多巴胺(DA)释放。硫酸吗啡 (MS) 降低中位隆起 DA 周转并增加长期接受 MS 治疗而耐受阿片类药物的大鼠血浆 PRL 浓度的能力得到了检验。在初始大鼠中，MS（10 mg/kg，皮下注射）导致血清 PRL 平均增加 79 ng/ml。用增加的MS剂量治疗4天后，相同的MS剂量仅导致18ng/ml的增加，表明出现了对MS的PRL释放作用的耐受。在相同的动物中，也出现了对 MS 减缓中位隆起 DA 周转能力的耐受，MS 降低中位隆起 DA 周转的作用减弱就证明了这一点。 MS 和内源性阿片类药物通过减缓正中隆起的 DA 释放，明显增加了腺垂体 PRL 的释放速率。反过来，这会导致垂体催乳细胞的抑制张力降低，从而导致 PRL 释放速率加快。
Exogenous and endogenous opioids stimulate PRL [prolactin] release by the anterior pituitary. Morphine and the opioid peptides [D-Ala2, D-Leu5]enkephalin and .beta.-endorphin decreased dopamine (DA) release by nerve terminals in the median eminence. The ability of morphine sulfate (MS) to decrease DA turnover in the median eminence and increase plasma PRL concentrations in rats made tolerant to opioids by chronic treatment with MS was examined. In naive rats, MS (10 mg/kg, s.c.) caused a mean increase in serum PRL of 79 ng/ml. After treatment with increasing MS doses for 4 days, the same MS dose caused an increase in only 18 ng/ml, indicating that tolerance to the PRL-releasing action of MS occurred. In the same animals, tolerance to the ability of MS to slow DA turnover in the median eminence also occurred, as demonstrated by an attenuation of the action of MS to decrease median eminence DA turnover. MS and endogenous opioids apparently increase the rate of PRL release from the adenohypophysis by slowing DA release from the median eminence. This, in turn, results in a decrease in the inhibitory tone exerted on pituitary lactotropic cells and, consequently, a greater rate of PRL release.