Fig. 6. Effects of Sazetidine-A (2 mg/kg) and epibatidine (10 μg/kg) on the mean frequency (Hz) of action potentials of single locus coeruleus neurons. After a baseline recording of 200 s, Sazetidine-A or epibatidine was injected subcutaneously. A slight decrease in firing rate after Sazetidine-A was observed. In contrast, a marked increase in firing rate after epibatidine was observed 200 s after injection, which peaked 1,000 s after injection.