Neuronal delayed-rectifier and M-type potassium channels (Kv/KCNQ channels)

Neuronal delayed-rectifier and M-type potassium channels are essential components of the neuronal membrane that regulate electrical signaling and excitability [1, 3]. Delayed-rectifier channels, such as those in the Kv1, Kv2, and Kv3 families, primarily mediate the repolarization phase of the action potential, ensuring rapid recovery for subsequent firing [12, 15]. M-type channels, composed of Kv7 (KCNQ) subunits, generate a slow, non-inactivating current that stabilizes the resting membrane potential and governs the threshold for repetitive firing [5, 10]. Together, these channels act as a brake on neuronal activity, and their dysfunction is a hallmark of hyperexcitability disorders like epilepsy and neuropathic pain [3, 12]. Pharmacological activation of these channels, particularly the M-type current, is a proven therapeutic approach for treating seizures, while their inhibition can be used to enhance neurotransmission or study neuronal function [1, 5]. However, drugs targeting these channels must be carefully designed to avoid off-target effects on cardiac potassium channels, which could lead to life-threatening arrhythmias [1, 14].

Other names

Voltage-gated potassium channelsI_K(DR) and I_K(M) channelsNeuronal K+ channelsKv2.1 and Kv7 channels

Drugs targeting these channels act as either openers (activators) or blockers (inhibitors). Openers, such as retigabine, shift the voltage-dependence of activation to more negative potentials, enhancing potassium efflux and hyperpolarizing the neuron to reduce excitability [5]. Blockers, such as XE-991 or 4-aminopyridine, inhibit the outward potassium current, leading to membrane depolarization and increased neuronal firing [1, 12].