大鼠尾核微量注射γ—氨基丁酸对尾核痛反应神经元放电的影响

EFFECT OF MICROINJECTION OF GABA INTO THE CAUDADE NUCLEUS ON ELECTRICAL DISCHARGES OF NOCICEPTIVE NEURONS IN CAUDATE NUCLEUS OF RAT

在53只成年Wistar大鼠上，用玻璃微电极引导神经元放电，观察了尾核内注射γ-氨基丁酸（GABA）后，尾核痛反应神经元放电的变化和印防己毒素（picrotoxin，PIC）对GABA作用的阻断效应。尾核内每2分钟分别注射GABA25，50，100μg／2μl，尾核痛兴奋神经元（painexcitationneurous，PEN）诱发放电频率减少，潜伏期延长；痛抑制神经元（paininhibitonneurons，PIN）放电抑制时程缩短，放电频率增加。PEN和PIN电活动反应与GABA剂量间呈量效关系。尾核内注射三种剂量GABA引起的上述PEN和PIN放电变化可被每分钟腹腔注射PIC250μg／1ml所阻断。综上表明，GABA可通过同时影响尾核PEN和PIN的电活动而产生镇痛效应。

The characteristics of glass microelectrode recorded electrical activity of nocicep-tive neurons in the caudate nucleus elicited by microinjection of GABA and blockage bypicrotoxin (PIC) were studied in 53 Wistar rats. The results showed that GABA (25,50, 100 μg/2 μ1 every 2 min) inhibited the activity of pain excitation neurons (PEN),as shown by decreased frequency and increased latency, but enhanced the activity of pian inhibition neurons (PIN), as shown by shortened duration and increased dischargefrequency. Both activities are highly dose-dependent and could be blocked by PIC (ip250 μg, 1 ml/1 min).