Figure 11.

Subacute exposure to a single dose of nicotine primes aversion to IP stimulation in IP^ChR2 mice. Nicotine primed aversion was tested in RTPP on day 1 of the experiment and the light-simulated side of the test compartment was reversed on day 10. A, Home cage locomotion is suppressed by acute administration of nicotine independent of genotype. IP^ChR2 and control mice were given subcutaneous nicotine injections (0.3 mg/kg) and returned to the home cage for activity monitoring from 1 to 16 min after administration on day 1. Baseline activity was measured in the same cohort of mice in a prior trial of home cage locomotion without nicotine. ****Main effect of drug, F_(1,24) = 46.01, p < 0.0001. Cohort of 11 IP^ChR2 and 15 control mice. B–E, Results of a two-session nicotine-primed RTPP experiment with side reversal on day 10 in a cohort of 9 IP^ChR2 and 14 control mice. B, IP^ChR2 mice treated with nicotine show aversion to IP stimulation on day 1. *Post hoc test: multiple-hypothesis-corrected t test of day 1 effect of genotype: t₍₄₂₎ = 2.325, p = 0.05. C, Comparison of day 1 and day 10 of the reversal experiment shows that IP^ChR2 mice change side preference consistent with nicotine-primed aversion for the light stimulus. ****Post hoc test: multiple-hypothesis-corrected t test of Cre effect of day: t₍₂₁₎ = 6.185, p < 0.0001. D, Examples of the pattern of shuttle box activity in control and ChR2 mice selected from the day 1 results in B. The side paired with light stimulation is shaded in blue. E, Rapid development of nicotine-primed aversion in the day 1 trial shown in B. A significant difference is observed between genotypes in the initial 5 min epoch. *Post hoc test: multiple-hypothesis-corrected t test between genotypes for first 5 min epoch: t₍₆₃₎ = 2.54, p = 0.04.