Exploring the interoceptive stimulus effects of nicotine and varenicline

Publication date: June 2019Source: Pharmacology Biochemistry and Behavior, Volume 181Author(s): Brady M. Thompson, Scott T. Barrett, Rick A. BevinsAbstractLearning processes associated with nicotine influence the development of addiction to tobacco products. In the present report, we are interested in the interoceptive stimulus effects of nicotine acquiring control over appetitive behaviors – specifically, reward seeking. Also of interest is the current smoking cessation drug, varenicline (Chantix®). Varenicline, with its nicotine-like stimulus effects, can decrease withdrawal and cravings for a subset of individuals addicted to nicotine, though relapse is still common. We trained rats (N = 48) with nicotine (0.4 mg/kg, SC) as an excitatory stimulus (i.e., paired with sucrose) in a drug-discriminated goal-tracking (DGT) task. There was no access to sucrose on interspersed saline days. After acquisition of the initial nicotine-saline discrimination, rats were separated into four groups to test discrimination reversal and drug substitution. The control group maintained nicotine as the excitatory stimulus (NIC+). The substitution group had varenicline (1 mg/kg) replace nicotine as the stimulus paired with sucrose (VAR+). One reversal group had nicotine signal the absence of sucrose (i.e., now available on intermixed saline sessions; NIC−). The last group was similar to the NIC− group except varenicline replaced nicotine on non-reinforced sessions (VAR−). We foun...
Source: Pharmacology Biochemistry and Behavior - Category: Biochemistry Source Type: research