α2δ-1 subunit of voltage-gated calcium channels

Class

gabapentinoid; selective α2δ-1 ligand; reported ~23-fold greater in vitro binding potency than pregabalin (IC50 4.0 nM vs 92.0 nM) with lower measured brain-tissue exposure in preclinical models

Pathway

binds the α2δ-1 subunit of voltage-gated calcium channels, reducing calcium influx and consequent release of excitatory neurotransmitters (e.g. glutamate, substance P), decreasing neuronal excitability and nociceptive transmission

The α2δ-1 subunit is an accessory protein of voltage-gated calcium channels found on neurons throughout the peripheral and central nervous system, with particularly high expression in the dorsal horn of the spinal cord after nerve injury or inflammation. It regulates how much calcium enters the nerve terminal in response to electrical signaling. Because calcium influx triggers release of excitatory neurotransmitters such as glutamate and substance P, molecules that bind α2δ-1 and reduce this trafficking of calcium channels to the cell surface dampen the transmission of pain signals without blocking the channel pore directly. This mechanism, shared by the gabapentinoid drug class, is used broadly in neuropathic pain, certain seizure disorders, and some anxiety-related conditions, where excessive neuronal excitability contributes to symptoms. A related calcium-channel subunit, α2δ-2, is expressed more in the cerebellum and other regions tied to motor coordination and sedation; compounds designed for greater selectivity toward α2δ-1 over α2δ-2 aim to preserve the pain-modulating benefit while reducing central nervous system side effects such as dizziness or drowsiness that are common with less selective agents in this class.