Regulation Of Neuronal Excitability, M Currents And Na Currents By NGF In SCG Neurons

M current is a low threshold, slow-activated, non-inactivating, voltage- and time-dependent potassium current first described in bullfrog sympathetic neurons by Brown and Adam in 1980. Activation of M₁-type muscarinic receptor profoundly inhibits M current, hence it is named "M current", and the channel underlying is called M channel. M current is observed in many central and peripheral neurons including cortex, hippocampus, sympathetic, and sensory neurons and shows to be modulated by a variety of receptor types. M current plays a crucial role in stabilization of the membrane potential and regulation of neuronal excitability because it is the only sustained current activated at voltage near the threshold for action potential initiation.Heteromeric assembly of KCNQ2 and KCNQ3 subunits underlie the molecular composition of M channel. Mutation of these subunits leads to epilepsy condition known as "benign familial neonatal convulsion" (BFNC). Retigabine, the first M channel opener, induces neurons hyperexcitability, and is potentially useful for treatment of convulsion and epilepsy. Cognition-enhancer Linopirdine and XE991, known as specific blockers of M channel are suggested to improve the memory...