Gamma-aminobutyric acid-gated chloride channel (GABA-Cl) (GABA-Cl)

Invertebrate GABA-gated chloride channels (GABA-Cls) are essential inhibitory neurotransmitter receptors found in the nervous systems of nematodes, including the heartworm Dirofilaria immitis and various hookworm species (Accardi et al., 2012; Wolstenholme, 2012). These receptors belong to the Cys-loop superfamily of ligand-gated ion channels and are primarily responsible for mediating muscle relaxation and coordinating locomotion by allowing the influx of chloride ions upon activation by gamma-aminobutyric acid (GABA) (Feng et al., 2002). In parasites, these channels are often encoded by the unc-49 gene family and are localized at the neuromuscular junctions (Beech et al., 2010). They represent a major target for anthelmintic therapy, as their modulation leads to the paralysis and eventual expulsion or death of the parasite (Raymond et al., 2000). Drugs such as piperazine act as direct agonists at these receptors, while macrocyclic lactones like ivermectin and moxidectin can act as potent allosteric modulators (Yates et al., 2003). Because these invertebrate receptors possess distinct pharmacological profiles compared to their mammalian counterparts, they offer a degree of selective toxicity, although care must be taken in hosts with compromised blood-brain barriers (Menez et al., 2012). Ongoing research into these channels is critical for monitoring and overcoming anthelmintic resistance in both veterinary and human medicine (James et al., 2009).

Other names

UNC-49GABA receptorInvertebrate GABA receptorNematode GABA-gated chloride channelGABA-gated ion channel

Agonism or positive allosteric modulation of the chloride channel leading to hyperpolarization of nerve or muscle cells, resulting in flaccid paralysis of the parasite.