L-谷氨酸及其拮抗剂对大鼠脑片旁巨细胞外侧核神经元自发放电的影响

Effects of L-Glutamic Acid and Its Antagonist on Spontaneous Discharge of Nucleus Paragigantocellularis Lateralis Neurons in Brainstem Slice in Rat

作者在大鼠脑干脑片穷巨细胞外侧核（PGCL）区，用多管微电泳技术观察了微电泳谷氨酸（L－Glu）及其拮抗剂DL－2-氨酸-5-磷酸戊酸（AP5）对神经元自发放电的效应及AP5对L－Glu作用的影响。在51片脑片PGCL区共记录136个自发放电稳定的神经元，主要呈重复波电样式。L-Glu和AP5对自发放电约有兴奋、抑制和无影响三种效应，各占所测试神经元的80．65％、8．06％、11．29％（L－Glu）和28．00％、8．00％、64．00％（AP5）。兴奋反应呈量效依赖关系。AP5部分地阻断部分神经元（71．87％）对L－Glu的兴奋作用。结果表明大鼠离体脑片PGCL区种经元自发放电样式主要是重复放电，并从细胞水平上提示PGCL区有起递质作用的内源性兴奋性氨基酸（FAA）。

We studied the effects of iontophoretic application of L- glutamic acid (L- Glu) and its antagonist DL-2-amino-5-phosphonovaleric acid(AP5) on the spontaneous discharge of the nucleus paragigantocellularis lateralis (PGCL) neurons and the influence of AP5 on L-Glu effect in brainstem slice in rat with the multibarrel microelectrode techniques. One hundred and thirty six units with stable spontaneous discharge were recorded in 51 rat brain slices, their discharge pattern being primarily a repetitive one. Both L-Glu and AP5 showed three kinds of effect on the PGCL neuronal spontaneous discharge: excitatory, inhibitory and noeffect, with the percentage of 80.65%, 8.06%, 11.29% for L-Glu and 28.00%, 8.00%64. 00% for AP5 of the neurons tested, espectively. The excitatory effect showed a dose response relationship. AP5 could block partially the excitatory effect of L-Glu on most neurons tested (71.87%). The results indicated that the neurons in PGCL in rat brain slice in vitro principally showed a spontaneous dicharge with a repetitive firing pattern, and suggested that at cellular level their existed endogeneous excitatory amino acid as neurotrans mitter in PGCL and the neurons there possessed EAA receptors of both N-methyl-D-aspar tate (NMDA) and non-NMDA subtypes.