下丘脑背内侧核注射纳洛酮对束旁核痛兴奋单位放电的影响

Effect of injection of naloxone into the hypothalamic dorsomedial nucleus on the discharges of pain sensitive units in the parafascicular nucleus of rat

用玻璃微电极记录大鼠丘脑束旁核痛兴奋单位(PfPE)放电。观察到下丘脑背内侧核(DMH)微量注射纳洛酮(Nx)后:(1)PfPE的自发和痛诱发放电频率增加,时程延长;(2)部份PfPE的自发放电类型由散在单脉冲变成散在间簇状或完全的簇状发放,而窟诱发放电类型由持续性发放转变为间断性暴发式放电。本实验提示:DMH局部的内源性阿片肽对PfPE放电活动有抑制性调控作用。

Experiments were carried out on rats. The nociceptive unit discharges of pa-rafascicular nucleus ( PfPE ) evoked by noxious stimulation were recorded with gla-ss-microelectrode. The effect of injection of naloxone (NX 2μg/1μ1) into the hypothalamic dorsomedial nucleus (DMH) was observed. The results were as follows: ( 1 ) After injection of NX, both the firing rate and the duration ofnociceptive discharge of PfPE units were significantly increased. ( 2 ) After injection of NX, the discharge parttern of some PfPE units changed from dispersed into dispersed-bursting or bursting. (3) Normal saline injected into DMH did not affect the frequency nor the pattern of the discharges of PfPE units. These results indicate that endogenous opiate-like substances in DMH may take part in the modulatory action of DMH on PfPE units.