Enables acetylcholine-gated cation-selective channel activity. Contributes to acetylcholine receptor activity. Involved in regulation of synaptic vesicle exocytosis. Acts upstream of or within several processes, including behavioral response to nicotine; chemical synaptic transmission; and regulation of dopamine secretion. Located in dopaminergic synapse and external side of plasma membrane. Part of acetylcholine-gated channel complex. Is integral component of presynaptic membrane. Is expressed in several structures, including alimentary system; genitourinary system; integumental system; nervous system; and sensory organ. Human ortholog(s) of this gene implicated in autosomal dominant nocturnal frontal lobe epilepsy 1 and nicotine dependence. Orthologous to human CHRNA4 (cholinergic receptor nicotinic alpha 4 subunit). [provided by Alliance of Genome Resources, Apr 2022]