Strauss P
Physiol Bohemoslov. 1986;35(4):289-98.
The inhibitory effect of gamma-aminobutyric acid (GABA) and its synthetic derivative baclofen were compared in frog cerebellum in vitro. Baclofen inhibited synaptic transmission from parallel fibres to the Purkinje cells in EC50 concentrations approximately 200-fold lower than for GABA. In addition to its inhibitory effect, GABA induced temporary facilitation of responses in the dendrite zone by a mechanism dependent on the presence of a normal Cl- concentration; the inhibitory phase was only partly sensitive to reduction of the Cl- concentration in the medium and to the administration of picrotoxin. The action of baclofen, which was unaffected by these treatments, requires an intact catecholamine and serotonin pool, since it is ineffective in reserpine-treated animals. Both substances also influence the excitability of parallel fibres. In solutions with a high Mg2+ and a low Ca2+ concentrations GABA inhibits the spontaneous activity of Purkinje cells by acting on the postsynaptic membrane of the soma and the primary dendrites. The effect of baclofen is evidently the outcome of inhibition of transmitter release from presynaptic endings.
在体外对青蛙小脑比较了γ-氨基丁酸（GABA）及其合成衍生物巴氯芬的抑制作用。巴氯芬抑制从平行纤维到浦肯野细胞的突触传递，其半数有效浓度（EC50）比GABA低约200倍。除抑制作用外，GABA通过一种依赖于正常氯离子浓度存在的机制诱导树突区域反应的暂时易化；抑制阶段仅部分受培养基中氯离子浓度降低和给予苦味毒的影响。巴氯芬的作用不受这些处理的影响，其作用需要完整的儿茶酚胺和5-羟色胺库，因为在利血平处理的动物中它无效。这两种物质也影响平行纤维的兴奋性。在高镁离子和低钙离子浓度的溶液中，GABA通过作用于胞体和初级树突的突触后膜来抑制浦肯野细胞的自发活动。巴氯芬的作用显然是抑制突触前末梢递质释放的结果。
