T-type

T-type calcium channels are a type of voltage-gated calcium channel that are named for their transient (short-lasting) opening and closing behavior. They are found in various types of tissue, including the brain, heart, and smooth muscle. T-type calcium channels are involved in various physiological functions, such as neuronal firing, cardiac pacemaking, and muscle contraction.

Structure

T-type calcium channels are composed of several subunits, including the alpha-1 subunit, which forms the pore through which calcium ions pass. The alpha-1 subunit is encoded by three different genes, CACNA1G, CACNA1H, and CACNA1I, which give rise to the Cav3.1, Cav3.2, and Cav3.3 channels, respectively.

Function

T-type calcium channels are involved in various physiological functions. In neurons, they contribute to the generation of action potentials, which are the electrical signals that neurons use to communicate with each other. In the heart, they contribute to the pacemaking activity of the sinoatrial node, which is the natural pacemaker of the heart. In smooth muscle, they contribute to the contraction of the muscle.

Clinical significance

Mutations in the genes that encode the alpha-1 subunit of T-type calcium channels can lead to various disorders. For example, mutations in CACNA1G can cause spinocerebellar ataxia, a neurological disorder characterized by uncoordinated movement. Mutations in CACNA1H can cause childhood absence epilepsy, a type of epilepsy characterized by brief, sudden lapses in consciousness.

See also

• Voltage-gated calcium channel
• Calcium channel blocker
• Spinocerebellar ataxia
• Childhood absence epilepsy

T-type Resources
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