Figure 10.

HCN2 channels (local and distant) and HCN2 channel agonists restore associative learning capacity in nicotine-exposed embryos. Associative learning analysis for stage 45–50 tadpoles with indicated treatments. Lamotrigine (LT, stages 10–35) or gabapentin (GP, stages 10–35). (A) The training regime in the behavior analysis machine consisting of an innate preference test, a training phase (acquisition), a rest period, and a learning probe. Automated software executed a training cycle where animals received a shock when occupying the red half of the arena. Training, rest, and testing sessions were repeated a total of six times across the trial. (B) Quantification of time spent by each tadpole in the red-lit area during the final testing probe for each of the indicated treatments. Percentage of time spent by each tadpole in red light for each experimental group are Controls—24%, Nicotine—60%, Nicotine+HCN2-WT 2/4 dorsal—32%, Nicotine+HCN2-WT 2/4 ventral—27%, Nicotine+LT—28%, and Nicotine+GP—24%. Data represented as mean ± SD, ***p < 0.001, n.s.: non-significant (one-way ANOVA with Tukey’s post hoc test for N > 20 tadpoles for each treatment group).