Fig. 3

The odor-evoked responses of regional blood flow in the olfactory bulb to intravenous injection of nicotine without (a) and with (b) dihydro-β-erythroidine. The mean values of blood flow in the olfactory bulb during a 60-s period after the onset of odor stimulation were expressed as percentage of the pre-stimulus basal values (−30 to 0 s). In b, nicotine was injected 20–25 min after intravenous administration of dihydro-β-erythroidine (DHβE, 5 mg/kg). Each column and vertical bar represent the mean ± SEM (a: n = 6, b: n = 4). *p < 0.05; significantly different from the response before nicotine injection determined by a paired t-test