【摘要】 用脊髓薄片全细胞电压钳法观察激活γ 氨基丁酸B亚型受体 (GABABR)对大鼠脊髓背角胶状质(SG)神经元活动的影响。选择性GABABR激动剂baclofen减少所有被记录SG神经元 (n =15)的微小兴奋性突触后电流 (mEPSCs)的发放频率 ,同时引起一缓慢的抑制性 (外向 )膜电流并伴有膜电导增加。细胞内电泳G蛋白偶联受体抑制剂 (GDP β S)抑制被钳制神经元的G蛋白偶联受体后 ,baclofen引起的缓慢外向电流被抑制 ,但对mEPSC频率的减低作用依然存在。结果提示脊髓内baclofen敏感的GABAB 受体被激活后直接引起SG神经元超极化并能减少突触前递质的释放更多还原

【Abstract】 Whole cell voltage clamp recording technique was used to examine the effects of γ aminobutyric acid B receptor (GABA BR) activation on the neuronal activities in the substantia gelatinosa (SG) of rat spinal cord slice. Bath application of a GABA BR selective agonist, baclofen (10 μmol/L, 30 s), resulted in a frequency reduction of miniature excitatory postsynaptic currents (mEPSCs), together with a slow inhibitory (outward) membrane current in all tested SG neurons ( n =15). The membrane conductance of the SG neurons increased during the baclofen action. After the postsyanptic GABA BR being inhibited by intracellular G protein coupled receptor inhibitor GDP β S, the baclofen induced slow outward currents were depressed, while the effect of frequency reduction on mEPSCs persisted. The results indicate that activation of baclofen sensitive GABA BR in spinal cord directly hyperpolarizes SG neurons, and can presynaptically reduce neurotransmitter release.更多还原