Nordmann J J, Dayanithi G, Cazalis M
Exp Brain Res. 1986;61(3):560-6. doi: 10.1007/BF00237581.
Rat neurointermediate lobes and neurohypophyses separated from the pars intermedia were stimulated in vitro in the presence of either D-Ala2, D-Leu5-enkephalin (DADLE), a Leu-enkephalin stable analogue or FK 33-824 a Met-enkephalin stable analogue. Secretion of vasopressin (AVP) and oxytocin (OT) was produced by either a Ca2+-ionophore or with electrical stimulation or by K+-induced depolarization. These opioid peptides and their antagonist naloxone did not affect basal nor evoked hormone release. Furthermore, they did not affect the evoked calcium uptake induced with electrical stimulation. These findings were confirmed using a preparation of isolated neurosecretory nerve endings. Further, dopamine had no effect on the K+-induced AVP release although a crude extract of the pars intermedia abolished the electrically-evoked and reduced considerably the potassium-evoked AVP release. It is concluded that in the neurohypophysis neither Leu- and Met-enkephalin nor dopamine affect the secretion-coupling mechanism at the level of the neurosecretory nerve endings.
从中间部分离出的大鼠神经中间叶和神经垂体在体外进行刺激，刺激时存在D - Ala2、D - Leu5 - 脑啡肽（DADLE，一种亮氨酸脑啡肽稳定类似物）或FK 33 - 824（一种甲硫氨酸脑啡肽稳定类似物）。通过钙离子载体、电刺激或钾离子诱导的去极化作用可产生抗利尿激素（AVP）和催产素（OT）的分泌。这些阿片肽及其拮抗剂纳洛酮既不影响基础激素释放，也不影响诱发的激素释放。此外，它们不影响电刺激诱导的诱发钙摄取。使用分离的神经分泌神经末梢制剂证实了这些发现。此外，多巴胺对钾离子诱导的抗利尿激素释放没有影响，尽管中间部的粗提物消除了电诱发的抗利尿激素释放，并显著降低了钾诱发的抗利尿激素释放。得出的结论是，在神经垂体中，亮氨酸脑啡肽、甲硫氨酸脑啡肽和多巴胺均不影响神经分泌神经末梢水平的分泌偶联机制。
