Fig. 3.

Nicotine increases DRN neuronal firing rate. A: example frequency histogram from a DRN neuron that responded to bath application of 1 μM nicotine with an increase in action potential (AP) frequency. Inset: representative traces before (Control) and after perfusion with nicotine. B: mean change in firing frequency following application of 1 μM nicotine. Responsive cells were identified by comparing firing frequency before and during nicotine application (see materials and methods). Black bars represent recordings in artificial cerebrospinal fluid (aCSF), while gray bars represent recordings in aCSF + 12 μM phenylephrine. Bars represent means ± SE. C: response prevalence of the effects of 1 μM nicotine on AP frequency for cells recorded in normal aCSF (black bars) and aCSF + 12 μM phenylephrine (gray bars). B and C: numbers inside bars indicate n for each condition.