下丘脑—垂体神经内分泌途径参与刺激弓状核的镇痛过程

HypothalamoPituitary Neuroendocrine Pathway is Involved in Arcuate Stimulation-Produced Antinociception

以 H 刀游离弓状核区,用行为测痛结合放射免疫分析,观察了电刺激游离弓状核(ARC)的镇痛效应及血浆、垂体和间脑β-内啡肽含量的变化。主要结果是:(1)刺激正常的 ARC 停止后,立即出现镇痛作用,持续30min,而刺激游离的 ARC 停止后,镇痛并不立即出现,而要过5min 后才出现,也持续30min。(2)刺激 ARC 后,间脑、垂体和血浆β-内啡肽含量增高。实验结果提示:刺激ARC 可引起垂体β-内啡肽的释放。与外周阿片受体结合或循垂体门脉系统逆流入脑内产生镇痛,说明 ARC-垂体神经内分泌途径在很大程度上参与刺激 ARC 镇痛。

The effect of hypothalamic arcuate nucleus(ARC)stimulation on pain threshold and on plasma, pituitary and cerebral β-endorphin(β-END)content was investigated in rats with isolated ARC by means of pain measurement and radioimmunoassay.The main results were as follows:(1) Antinociceptive effect appeared only 5 minutes after ARC stimulation in rats with isolated ARC,while in normal rats antinociception appeared immediately after ARC stimulation.(2)β-END content in plasma,pituitary and diencephalon was increased after ARC stimulation.Results suggest that ARC stimulation might promote the release of pituitary β-END,which can enter into blood to produce antinociception peripherally and can enter into brain through retrograde flow in portal system to induce antinociception centrally,i.e.,the hypothalamo-pituitary neuroendocrine pathway might be involved in this antinociception.