调制多觉型伤害性感受器持续放电的体液因素

利用复合致痛剂引起大鼠皮肤多觉型伤害性感受器(PMN)持续放电的模型,发现刺激坐骨神经中枢端对 PMN 持续放电有显著的抑制或先易化后抑制效应。通过交叉灌流,刺激供血动物的坐骨神经也可对受血动物的 PMN 持续放电产生类似的效应。注射刺激坐骨神经动物的血清,可显著影响 PMN 的活动。大部分单位的抑制效应不被纳洛酮翻转。对吗啡耐受的动物,刺激坐骨神经仍可引起抑制效应。预先利血平化,则使刺激的易化效应基本取消。结果证实,躯体神经传入冲动诱发体液因素调制 PMN 的持续性活动。其中参与抑制效应的因子可能有阿片类与非阿片类,参与易化效应的因子可能是儿茶酚胺。

HUMORAL FACTORS IN THE MODULATION OF SUSTAINED DISCHARGES OF POLYMODAL NOCICEPTORS

By using a model of sustained discharges of polymodal nociceptors(PMN)due to injection of a compound algogenic substance into the skin in anesthetized rats,it was found that stimulation of the sciatic nerve inhibited or facilitated at first andthen inhibited the PMN sustained discharges markedly.In a crossperfused prepa-ration,stimulation of the sciatic nerve of donor rat caused the similar effects on sus-tained discharges of PMN of the recipient rat.Injection of the animal serum afterstimulation of the sciatic nerve affected PMN activity obviously.The inhibitorycourse of most units could not be reversed by naloxone.In the animal toleranceto morphine,the effects of stimulation of the sciatic nerve could still be obtained.Preadministration of reserpine almost completcly abolished the facilitatory effect.The results indicate that sustained activity of PMN could be modulated by somehumoral factors due to somatic afferents.The inhibitory substances in the humoralfactor seem to be both opioid and nonopioid in nature.The facilitatory substanceseem to be a catecholamine.