Nematode muscle gamma-aminobutyric acid receptor (UNC-49) (UNC-49)

The nematode muscle GABA receptor, primarily represented by the UNC-49 complex, is a ligand-gated chloride channel essential for inhibitory signaling at the neuromuscular junction (Bamber et al., 1999). In nematodes such as Caenorhabditis elegans and Ascaris suum, this receptor mediates muscle relaxation, which is critical for the undulating movement and locomotion of the organism (Raymond et al., 2000). It is a member of the Cys-loop receptor superfamily and typically functions as a heteromer composed of different subunits (e.g., UNC-49B and UNC-49C) that provide distinct pharmacological properties (Bamber et al., 1999). This receptor is a major target for anthelmintic drugs such as piperazine, which acts as a selective GABA agonist to induce flaccid paralysis in the parasite, allowing it to be expelled from the host's body (Martin, 1997). Understanding the structural and functional differences between nematode UNC-49 receptors and vertebrate GABA_A receptors is crucial for developing selective antiparasitic agents with minimal host toxicity (Accardi et al., 2012).

Other names

Nematode muscle GABA_A receptorUNC-49 receptorNematode GABA-gated chloride channelGABA-A-like nematode receptor

Agonists bind to the receptor complex at the neuromuscular junction, triggering the opening of an integral chloride-selective pore. The resulting influx of chloride ions hyperpolarizes the muscle cell membrane, inhibiting contraction and leading to flaccid paralysis of the nematode (Martin, 1997; Bamber et al., 1999).