Cocaine self-administration in rats lacking a functional trpc4 gene

Abstract

The canonical transient receptor potential (TRPC) family of Ca 2+ permeable, non-selective cation channels is abundantly expressed throughout the brain, and plays a pivotal role in modulating cellular excitability. Unlike other TRPC channels, TRPC4 subtype expression in the adult rodent brain is restricted to a network of structures that receive dopaminergic innervation, suggesting an association with motivation- and reward-related behaviors. We hypothesized that these channels may play a critical role in dopamine-dependent drug-seeking behaviors. Here, we gathered data testing trpc4 knockout (KO) rats and wild-type (WT) littermates in the acquisition of a natural sucrose reward (10 days), and cocaine self-administration (13 days) at 0.5 mg/kg/infusion. Rats lacking the trpc4 gene ( trpc4 -KO) learned to lever press for sucrose to a similar degree as their WT controls. However, when they were switched to cocaine, the trpc4- KO rats had substantially reduced cocaine-paired lever pressing compared to WT controls. No obvious group differences in inactive lever pressing were observed, for any time, during cocaine self-administration.