Shin S H, Obonsawin M C, Van Vugt D A, Baby N, Jhamandas K
Department of Physiology, Queen's University, Kingston, Ont., Canada.
Can J Physiol Pharmacol. 1988 Nov;66(11):1381-5. doi: 10.1139/y88-226.
Prolactin release is controlled by prolactin-release inhibiting factor (PIF), possibly dopamine, and an unidentified putative hypothalamic prolactin-releasing factor (PRF). Morphine and related opioids may indirectly stimulate prolactin release by inhibiting PIF release and (or) by stimulating putative PRF release. In the present study, we have completely blocked the dopaminergic receptors in normal male rats by pretreatment with a large dose of pimozide (3 mg/kg) to demonstrate if putative PRF has a role in morphine-induced prolactin release. Morphine sulfate (10 mg/kg) was still able to stimulate prolactin release in the rat without any functional dopaminergic PIF receptors. When naloxone (3 mg/kg) was injected 20 min before the morphine in the pimozide-treated rat, plasma prolactin concentration was not affected by morphine indicating that the stimulatory effect of this opioid on prolactin release in the pimozide-pretreated rat was mediated by mu-receptors. We can conclude that morphine can stimulate prolactin release through a mechanism apparently independent of dopaminergic receptors, one possible route being through a putative PRF.
催乳素的释放受催乳素释放抑制因子（PIF，可能是多巴胺）以及一种尚未明确的假定下丘脑催乳素释放因子（PRF）的控制。吗啡及相关阿片类药物可能通过抑制PIF释放和（或）刺激假定的PRF释放来间接刺激催乳素释放。在本研究中，我们通过用大剂量匹莫齐特（3毫克/千克）预处理来完全阻断正常雄性大鼠的多巴胺能受体，以证明假定的PRF在吗啡诱导的催乳素释放中是否起作用。硫酸吗啡（10毫克/千克）在没有任何功能性多巴胺能PIF受体的大鼠中仍能刺激催乳素释放。当在匹莫齐特处理的大鼠中于吗啡注射前20分钟注射纳洛酮（3毫克/千克）时，血浆催乳素浓度不受吗啡影响，这表明该阿片类药物对匹莫齐特预处理大鼠催乳素释放的刺激作用是由μ受体介导的。我们可以得出结论，吗啡可通过一种明显独立于多巴胺能受体的机制刺激催乳素释放，一种可能的途径是通过假定的PRF。
