High-frequency stimulation on cell soma induces potentiation of intrinsic excitability in VTA dopaminergic neurons / 生理学报

ABSTRACT

Ventral tegmental area (VTA) is an important relay station of signal transmission in the reward system. The plasticity of VTA dopaminergic neurons directly influences actions of other regions of the reward system. Studies concerning the plasticity of VTA dopaminergic neurons focus mainly on synaptic plasticity, while much less attention has been given to the plasticity of intrinsic excitability of the neurons. The aim of the present study was to investigate the effect of high-frequency stimulation (HFS) on the plasticity of excitability of VTA neuron. Whole-cell patch-clamping was performed on VTA dopaminergic neurons in midbrain slices bathed with PTX, AP-5 and CNQX, and HFS was introduced to cell soma. The result showed that, after HFS induction the pharmacologically isolated neurons showed increased input resistance and firing frequency, as well as decreased rheobase. Meanwhile, the steady-state whole-cell current decreased, and the hyperpolarization-activated current (I(h)) decreased. These results suggest that HFS on soma induces a long-term potentiation of excitability in VTA dopaminergic neurons, and the underlying mechanism involves the changes of membrane current.