Munro G, Ludwig M, Landgraf R, Russell J A
Department of Physiology, University Medical School, Edinburgh, UK.
Neuropeptides. 1994 Aug;27(2):121-7. doi: 10.1016/0143-4179(94)90052-3.
Microdialysis was used to apply an osmotic stimulus (0.5 M NaCl-aCSF) into both supraoptic nuclei (SON) to investigate the role of endogenous opioid peptides in the control of both central and peripheral oxytocin release in response to this stimulus. There were no differences in central peptide release during direct hyperosmotic stimulation between groups of rats given either vehicle, morphine (5 mg/kg) or naloxone (5 mg/kg) intravenously. Naloxone potentiated oxytocin release into blood; this suggests that endogenous opioid peptides at the level of the neurohypophysis, but not in the SON are important modulators of oxytocin release to this stimulus. However morphine blocked oxytocin release into blood indicative of a central inhibitory action on the firing rate of oxytocin neurones, contrasted with insensitivity to morphine of oxytocin secretion from the dendrites stimulated directly by hyperosmolarity.
采用微透析技术向双侧视上核（SON）施加渗透刺激（0.5 M NaCl - 人工脑脊液），以研究内源性阿片肽在这种刺激下对中枢和外周催产素释放控制中的作用。静脉注射溶剂、吗啡（5 mg/kg）或纳洛酮（5 mg/kg）的大鼠组在直接高渗刺激期间，中枢肽释放没有差异。纳洛酮增强了催产素向血液中的释放；这表明神经垂体水平而非视上核中的内源性阿片肽是这种刺激下催产素释放的重要调节因子。然而，吗啡阻断了催产素向血液中的释放，这表明对催产素神经元的放电频率有中枢抑制作用，这与高渗直接刺激树突时催产素分泌对吗啡不敏感形成对比。
