Xu R K, McCann S M
Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235-9040.
Life Sci. 1989;45(17):1591-9. doi: 10.1016/0024-3205(89)90426-8.
The effect of i.v. injection of various doses of naloxone (NAL) on plasma adrenocorticotropin (ACTH) and prolactin (Prl) in conscious animals bearing an indwelling intrajugular catheter was assessed. The effects were evaluated in animals which were left undisturbed and in others subjected to either restraint or ether stress. The results revealed that the dose of 3 mg/kg of NAL significantly reduced basal Prl levels, whereas a dose of 6 mg/kg of NAL was required to block completely either ether or restraint stress-induced release of Prl. The behavior of ACTH contrasted with that of Prl. There was no effect whatsoever of the 3 mg/kg dose of NAL on either resting or stress-induced ACTH levels, whereas a 6 mg/kg or 12 mg/kg dose of NAL elevated resting ACTH levels and only partially attenuated the further elevation induced by stress in these animals. The results clearly indicate a NAL sensitive step in the control of resting and stress-induced Prl release but indicate that the control of resting and stress-induced release of ACTH is different in that the predominantly millimicron receptor blocker, NAL, can elevate ACTH at high doses and can only partially block the response to stress. In contrast to Prl where opioid peptide control is solely stimulatory, this control of ACTH secretion appears to have both stimulatory and inhibitory features.
评估了静脉注射不同剂量的纳洛酮（NAL）对颈静脉留置导管的清醒动物血浆促肾上腺皮质激素（ACTH）和催乳素（Prl）的影响。在未受干扰的动物以及遭受束缚或乙醚应激的动物中评估了这些影响。结果显示，3mg/kg的NAL剂量显著降低了基础Prl水平，而需要6mg/kg的NAL剂量才能完全阻断乙醚或束缚应激诱导的Prl释放。ACTH的表现与Prl相反。3mg/kg剂量的NAL对静息或应激诱导的ACTH水平均无影响，而6mg/kg或12mg/kg剂量的NAL可提高静息ACTH水平，并且仅部分减弱这些动物应激诱导的进一步升高。结果清楚地表明，在静息和应激诱导的Prl释放控制中有一个对NAL敏感的步骤，但表明静息和应激诱导的ACTH释放控制有所不同，因为主要的毫微摩尔受体阻滞剂NAL在高剂量时可提高ACTH水平，并且只能部分阻断对应激的反应。与阿片肽对Prl的控制仅具有刺激作用相反，ACTH分泌的这种控制似乎具有刺激和抑制两种特性。
