Fig. 3.

Responses of acetylcholine (ACh) release in the parietal cortex to focal electrical stimulation (at 200 μA) of the unilateral NBM ipsilateral to the parietal cortex in aged rats of the control group and nicotine-treated group. The level of extracellular acetylcholine measured every 3 min are plotted as the absolute values in the saline-treated control group (a, c, closed circles, n = 6) and the nicotine-treated group (b, d, open circles, n = 6). a, b ACh release measured in 6 rats from each group. c, d Summarized graph. Each point and vertical bar represents the mean ± SEM. **P < 0.01; significantly different from pre-stimulus control values (−3 to 0 min) using one-way repeated-measures ANOVA followed by Dunnett’s multiple comparison test