Cav1.2, but not Cav1.3, L-type calcium channel subtype mediates nicotine-induced conditioned place preference in miceo
Nicotine use is one of the most common forms of drug addiction. Although L-type calcium channels (LTCCs) are involved in nicotine addiction, the contribution of the two primary LTCC subtypes (Cav1.2 and 1.3) is unknown. This study aims to determine the contribution of these two LTCC subtypes to nicotine-induced conditioned place preference (CPP) responses by using transgenic mouse models that do not express Cav1.3 (Cav1.3−/−) or contain a mutation in the dihydropyridine (DHP) site of the Cav1.2 (Cav1.2DHP−/−). We found a hyperbolic dose dependent nicotine (0.1–1 mg/kg; 0.5 mg/kg optimum) effect on place preference in wild type (WT) mice, that could be prevented by the DHP LTCC blocker nifedipine pretreatment. Similarly, Cav1.3−/− mice showed nicotine-induced place preference which was antagonized by nifedipine. In contrast, nifedipine pretreatment of Cav1.2DHP−/− mice had no effect on nicotine-induced CPP responses, suggesting an involvement of Cav1.2 subtype in the nicotine-induced CPP response. Nifedipine alone failed to produce either conditioned place aversion or CPP in WT mice. These results collectively indicate Cav1.2, but not Cav1.3 LTCC subtype regulates, at least in part, the reinforcing effects of nicotine use.