Fig. 2: CSA dose responses for wildtype, HET, and homozygous Nav1 KO mice.

All graphs include the mean ± SEM. a Infusions earned in 10 sessions of CSA across genotype and across/within dose (n = 13–16 mice per genotype/dose). Nav1 KO mice self-administered more cocaine than wildtype and HET mice from session 3 on (upper graph represents genotype means across dose; *p < 0.05 between KO and wildtype/HET for post hoc comparisons across dose and within session). Lower graphs visualize responding within each dose (however no genotype-by-dose interaction was detected). b A visualization of the dose response curve for the number of cocaine infusions during last 3 sessions, which are averaged for each dose for mice of the indicated genotype. Nav1 KO mice displayed an upward shift in the dose response curve. c Visualization of the dose response curve for cocaine intake (mg/kg) during the last 3 sessions for each cocaine dose. Similar to the number of infusions, Nav1 KO mice displayed an upward shift in the dose-response curve for cocaine intake. d Active lever preference (i.e., the % of correct lever presses) during the last 3 sessions are shown for each of the 3 doses of cocaine. There was no difference in active lever presses among the groups of mice with different genotypes. e CSA was measured at two different doses (0.1 and 1.0 mg/kg) in Wt, Het and Nav1 KO mice (n = 13–16 mice per group) using a progressive ratio test, where the number of active lever presses required for receiving the next cocaine infusion is progressively doubled from that required for the previous infusion. The number of lever presses required to earn the last cocaine infusion (i.e., the last ratio) provides an assessment of their motivation for cocaine consumption. Nav1 KO mice achieved a significantly greater last ratio than wildtype or Het mice (*p < 0.05; main effect of genotype).