谷氨酸,γ—氨基丁酸及其拮抗剂对大鼠旁巨细胞外侧核神经元自…

采用多管微电极技术在２２只麻醉的ＳＤ大鼠观察了分别微电泳谷氨酸钠、γ－氨基丁酸及其拮抗剂ＤＬ－２－氨基－５－磷酸戊酸，荷包牡丹碱对旁巨细胞外侧核尾半侧神经元自发放电的效应和ＡＰ５对Ｌ－Ｇｌｕ，ＢＩＣ对ＧＡＢＡ作用的影响。结果显示：Ｌ－Ｇｌｕ使大多数被测试神经元（３０／３６个）兴奋，ＧＡＢＡ使全部受试神经元（ｎ＝５３）抑制、ＡＰ５，ＢＩＣ有兴奋，抑制和无作数被测试神经元（３０／３６个）兴奋，ＧＡＢＡ

Effects of L-glutamic acid, gamma-aminobutyric acid and their respective antagonists on spontaneous discharge of nucleus paragigantocellularis lateralis neurons in rats]

Using multibarrel microelectrode techniques, we studied the effects of iontophoretic application of L-glutamic acid (L-Glu), gamma-aminobutyric acid (GABA) and their respective antagonists DL-2-amino-5-phosphonovaleric acid (AP5), bicuculline (BIC) on the spontaneous discharge of the caudal half of nucleus paragigantocellularis lateralis (cPGCL) neurons (including respiratory related neurons) and the influences of AP5 and BIC on the effects of L-Glu and GABA respectively in 22 anesthetized spontaneously breathing Sprague-Dawley rats. The spontaneous discharges of all the cPGCL neurons tested were inhibited by GABA(n = 53). Most of the tested neurons were excitated by L-Glu (30/36). AP5 and BIC both showed three kinds of effects on the cPGCL neuronal spontaneous discharge; excitatory, inhibitory and no-effect. The excitatory effects of L-Glu and BIC and the inhibitory effects of GABA showed a dose-response relationship. AP5 could block partially the excitatory effect of L-Glu on a large part of neurons tested (14/19). BIC blocked, partially or completely, the inhibitory effect of GABA also on a large part of the neurons tested(18/24). The results implicate that there might exist endogenous L-Glu and GABA acting as neurotransmitters in the cPGCL area and excitatory amino acids (EAA, including NMDA and non-NMDA) and GABA-receptors on cPGCL neurons. These neurotransmitters and receptors may mediate the regulatory action of cPGCL on respiration and other functional systems.