Fig. 5.

The effects of nicotine and MPEP on activity in a cross maze. Groups of rats (N = 6 in each group) were treated with daily injections (s.c.) with saline or nicotine (0.4 mg/kg) for 8 days. Prior to the injection on day 1, the rats were placed in a cross maze for 30 min before being given an i.p injection of MPEP (5.0 mg/kg; filled columns) or saline (open columns). Thirty minutes after the injection, the rats were given a second s.c. injection of saline or nicotine (0.4 mg/kg), and entries into the arms of the cross maze counted for 20 min starting immediately after the second injection (acute treatment). The procedure was repeated on day 10 (repeated treatment). The data are expressed as means ± SEM. Significantly different from rats treated with s.c. saline ***P < 0.001; significantly different from rats tested after acute nicotine +P < 0.05