A conserved role of α2δ subunit of calcium channel in nicotine motivated behavior.

Identifying genetic variants associated with nicotine-motivated behavioral traits is an important strategy to understand the fundamental mechanisms underpinning smoking and tobacco abuse. For suitable emulation of behavioral phenotype with the full advantage of this invertebrate model, we newly established a worm model of nicotine seeking by Conditioned Cue Preference (CCP). We demonstrated that C. elegans also exhibited pivotal features of nicotine-motivated behaviors as in mammals. First, we identified the nicotine-elicited cue preference is mediated by nicotinic acetylcholine receptors in worms. Additionally, we exhibited dopamine is also required for the development of CCP. Subsequently, we identified the nAChRs subunits associated with the facilitation of nicotine preference. Accordingly, we validated human GWAS candidates associated with nicotine dependence involved in the role of those nAChR subunits. we addressed the cross-species functional validation to determine the GWAS candidate genes have authentic roles in nicotine seeking associated with tobacco abuse. The loss of function strain of CACNA2D3 orthologue, calcium voltage-gated channel auxiliary subunit alpha2delta 3, was tested for CCP. We also tested the knock-out (KO) strain of the CACNA2D2 orthologue, calcium voltage-gated channel auxiliary subunit alpha2delta 2, which is closely related to CACNA2D3 in the same family and shared the human smoking phenotypes. Our orthogonal test suggests the functional conservation of the 2{delta} subunit of calcium channel in nicotine motivated behavior.