M细胞腹侧树突内复合性突触后电位的抑制性成分

目的探查Mauthner细胞腹侧树突的复合性突触后电位的抑制性成分。方法电刺激鲫鱼皮肤,用微电极记录诱发的Mauthner细胞腹侧树突的突触后电位。分别改变刺激频率和刺激强度,经负向电流向腹侧树突内电泳Cl-,延髓表面滴加士的宁,观察电位变化。结果突触后电位具有频率和强度依赖性,同时具有氯离子浓度依赖性。滴加士的宁后,突触后电位幅度增加,甚至在原有去极化的基础上爆发动作电位。结论从皮肤到M细胞腹侧树突的通路由多突触组成;抑制性成分不仅投射到胞体还投射到腹侧树突,释放的递质可能是甘氨酸。

The Inhibitory Component of the Compound Postsynaptic Potentials in the Ventral Dendrite of Crucian Carp's Mauthner Cell Evoked by Skin Stimulation

Objective To explore the inhibitory component of the compound postsynaptic potentials(PSPs) in Mauthner cell's ventral dendrite.Methods Direct stimulation the skin of crucian carp,change the stimulus strength and the stimulus frequency or inject hyperpolarizing currents to the ventral dendrite through the Cl-filled microelectrode or drop strychnine to the surface of medulla,microelectrode were used to record the change of postsynaptic potentials in the ventral dendrite.Results The PSP amplitudes were stimulus strength-and frequency-and Cl-dependent within some limits.After dripping strychnine on the brain of crucian carp,the PSP amplitudes enhance greatly,even action potentials can break out.Conclusion It suggests that the afferent pathways from skin to M-cells contain both excited and inhibitory components,the inhibitory neurons project not only to the soma but also to the ventral dendrite,and the neurotransmitter released may be glycine.