T-type voltage-gated calcium channel (T-type VGCC) (T-type VGCC)

T-type voltage-gated calcium channels (VGCCs) are low-voltage-activated (LVA) channels that play a fundamental role in regulating the excitability and rhythmic firing patterns of neurons and cardiac cells (Source: UniProt, P19101). Unlike high-voltage-activated channels, T-type channels open at relatively negative membrane potentials, allowing them to influence the resting membrane potential and facilitate pacemaker activity (Source: PubMed, PMC2630027). These channels are composed of three main alpha-1 subunits: Cav3.1, Cav3.2, and Cav3.3, which are encoded by the CACNA1G, CACNA1H, and CACNA1I genes, respectively (Source: NIH Gene). Pathologically, overactivity or mutations in these channels are associated with absence epilepsy, neuropathic pain, and sleep disturbances (Source: PubMed, 25160744). Flunarizine is a non-selective calcium channel blocker that exhibits potent inhibitory effects on T-type channels, which contributes to its efficacy in migraine prophylaxis and the treatment of vertigo (Source: PubChem, CID 3363). By limiting calcium overload in neurons and vascular smooth muscle, flunarizine helps prevent the cascade of events leading to cortical spreading depression and vasospasm (Source: StatPearls, NBK482250). Its multi-target profile also includes activity at sodium channels and dopamine receptors, which influences its overall therapeutic and side-effect profile.

Other names

Low-voltage-activated calcium channelLVA calcium channelCav3 channelVoltage-dependent T-type calcium channel

Flunarizine acts as a calcium channel antagonist that binds to the alpha-1 subunits of T-type voltage-gated calcium channels, inhibiting the influx of calcium ions during low-threshold spikes (Source: PubChem, CID 3363). This inhibition reduces neuronal hyper-excitability and prevents intracellular calcium overload, which is a key factor in neuronal damage and migraine pathogenesis (Source: PubMed, 2443435).