Electrophysiological studies of synaptic transmission in the central and peripheral autonomic neurons.

1.交感节前神经元（SPN）的突触前调节：去甲肾上腺素（NA）抑制突触前快EPSP这种抑制作用可能是由于谷氨酸能突触前神经末梢上的α_2受体激活，引起终膜超极化和/或钙电导降低. SPN中儿茶酚胺能传递的受体和信号转导机制：SPN上的α_1和α_2受体分别介导慢EPSP和慢IPSP，α_1受体主要位于树突上，α_2受体主要位于索马体上。前者通过G蛋白和蛋白激酶C产生慢反应，后者仅通过G蛋白产生慢反应. SPN中的吲哚胺能和肽能传递：5-羟色胺（5-HT）和速激肽均引起Ca依赖性K电导降低，导致SPN的缓慢去极化和缓慢后超极化抑制。5-HT的作用是由5-HT_2受体介导的.豚鼠盲肠粘膜下神经元介导慢IPSP的细胞内信号转导：NA介导慢IPSP的细胞内信号转导机制如下：i）K电导的增加是由百日咳毒素敏感G蛋白的激活和IP_3从细胞内释放的Ca^2+的相应积累介导的。释放的Ca^<2+>与钙调素结合可能导致钾电导增加。

1. Presynaptic regulation of sympathetic preganglionic neurons (SPN) : Noradrenaline (NA) inhibits the fast EPSP presynaptically This inhibiton appeared to be due to activation of alpha_2 receptors on the gultaminergic presynaptic nerve terminals that might cause hyperpolarization and/or reduction of Ca conductance of the terminal membrane.2. The receptor and signal transduction mechanisms underlying the catecholaminergic transmission in SPNs : The alpha_1 and alpha_2 receptors on SPNs, respectively, mediate the slow EPSP and the slow IPSP.The alpha_1 receptors are endowed mainly on the dendrites and the alpha_2 receptors on the soma. The former produces the slow response via G-protein and proteinkinase C and the latter via G-protein alone.3. The indolaminergic and peptidergic transmissions in SPNs : Both serotonin (5-HT) and tachykinins cause reduction of the Ca-dependent K conductance that results in a slow depolarization and the inhibition of the slow afterhyperpolarization of SPNs. The 5-HT action is mediated by 5-HT_2 receptors.4. Intracellular signal transduction that mediates the slow IPSP in submucous neurons of the guinea-pig caecum : The mechanisms underlying intracellular signal transduction of the slow IPSP mediated by NA appeared to be following : i) the increased K conductance was mediated by the activation of pertussis toxin-sensitive G protein and the corresponding accumulation of intracellular Ca^<2+> released from the internal stores by IP_3. The binding of the released Ca^<2+> to calmoduline might result in an increase in potassium conductance.