微电泳锂盐对大鼠尾壳核痛反应神经元电活动的影响

EFFECT OF LITHIUM APPLIED IONTOPHORETICALLY ON ELECTRICAL ACTIVITIES OF PAIN--RELATED NEURONES IN CAUDATE--PUTAMEN NUCLEUS OF RAT

应用多管微电极离子微电泳技术,观察微电泳锂盐对大鼠尾壳核(CPN)痛反应神经元电活动的影响。实验结果表明,痛相关神经元(PRN)在CPN头区内呈现均匀的分布,但痛兴奋神经元(PEN)和痛抑制神经元(PIN)的分布可能不均匀,其中PIN主要分布在CPN的头前区,PEN则较集中于CPN头中心区。微电泳锂盐能抑制CPN头区内PEN的痛放电活动,并使PIN放电活动增加;这种PEN与PIN对锂盐的反应型式与它们对吗啡的反应型式呈正相关,提示锂盐的镇痛作用可能与内源性阿片样物质的释放有关。

Multi--barrelled micro--electrode has been used to observe further the effect of Li^+applied iontophoretically on electrical activities of pein related neurones (PRN) of therat caudate-putamen nucleus (CPN) and its mechanism of action was studied at the cellular level. It was found that PRN were homogeneously distributed throughout the headof CPN, but pain-excitation neurones (PEN) and pain-inhibition neurones (PIN) wereheterogeneously distributed. The PIN were mainly distributed in the anterior part, whilethe PEN primarily in the central part of the head of CPN. The results may provide aelue to understand the complicacy in the pain regulation mechanism undergoing in thehead of CPN. Li^+ iontophoresis could inhibit the discharges of PEN, while the dis-charges of PIN were activated. The interference modes of pain discharge of PEN andPIN induced by Li^+ iontophoresis were positively related to that induced by morphine.It was suggested that there existed some similarity in the mechanisms of analgesia in-duced by Li^+ and morphine. This, in turn, appears to support the suggestion that endo-genous opioid peptides and opioid receptors may be involved in tlle analgesic effect ofLi^+.