Synaptic Transmission and Modulation in the Autonomic Nervous System

1.脊髓外侧角细胞(CAT)中快EPSP(谷氨酸和天冬氨酸)、慢EPSP(去甲肾上腺素)和慢IPSP(去甲肾上腺素)递质释放的测定：用GASS-MS法测定脊髓外侧角组织切片自发和诱发的谷氨酸和天冬氨酸的释放。采用高压液相色谱仪测定同一组织制剂中去甲肾上腺素的释放量。侧角细胞内介导突触电位的受体特征及慢速PSP的细胞内信号转导分析：负责产生快速EPSP的谷氨酸受体70%为非NMDA型，30%为非NMDA型+NMDA型。大部分快速IPSP是由甘氨酸通过甘氨酸受体介导的，部分快速IPSP是由GABA通过GABA-A受体介导的。去甲肾上腺素分别通过α1和α2肾上腺素受体诱发慢的EPSP和IPSP。前者与蛋白激酶C激活引起的钙依赖性钾通道关闭有关，后者与G蛋白激活引起电压非依赖性钾通道开放有关。侧角细胞(CAT)的突触前抑制：这些细胞中的快速EPSP在突触前被去甲肾上腺素抑制。这种抑制是由于谷氨酸释放几率的降低。胃肠道(豚鼠)Meissner‘s神经元产生慢IPSP的细胞内信号转导：研究发现，由去甲肾上腺素递质诱发的Meissner’s神经元的外向突触电流不仅由激活G蛋白触发的K通道开放产生，而且还通过与前者同时发生的钙依赖性K通道的激活而产生。

1. Measurement of the release of transmitters mediating the fast EPSP (glutamate and aspartate), the slow EPSP (noradrenaline) and the slow IPSP (noradrenaline) in the spinal lateral horn cells (cat) : The spontaneous and evoked release of glutamate and aspartate from tissue slices of the lateral hoorn were measured by the gass-mass spectrometry. The release of noradrenaline from the same tissue preparation was measured by a high-pressure liquid chromatography.2. Characterization of the receptors mediating the synaptic potentials in the lateral horn cells (cat) and analysis of the intracellular signal transduction for the slow PSPs : The glutamate receptors responsible for production of the fast EPSP were a non-NMDA type in 70% of the cells and non-NMDA plus NMDA types in 30% of the cells. Most of the fast IPSP were mediated by glycine via glycine receptors, while some of the fast IPSP were mediated by GABA through GABA-A receptors. The slow EPSP and IPSP were evoked by noradrenaline via alpha-1 and alpha-2 adrenoceptors, respectively. The former was associated with closing of Ca-dependent K channels due to activation of protein kinase C, and the latter was accompanied by opening of voltage-independent K channels due to activation of G protein.3. Presynaptic inhibition in the lateral horn cells (cat) : The fast EPSP in these cells were inhibited presynaptically by noradrenaline. This inhibition was due to a lowering of the probability of glutamate release.4. Intracellular signal transduction that produces the slow IPSP in Meissner's neurons of alimental canal (guinea-pig) : It was found that the outward synaptic current evoked by the transmitter noradrenaline in Meissner's neurons were produced not only by opening of K channels triggered by activated G protein but also by activation of Ca-dependent K channels that occurred simultaneously with the former.