Figure 4.
The effect of intra-medial-prefrontocortical administration of URB597 (0.01 μg) on the firing rate of dorsal raphe 5-HT neurons. (A) Representative integrated firing rate histograms of 5-HT neuronal activity recorded from a rat that received an intra-vmPFC infusion of vehicle (top) or URB597 (bottom). Abscissa represents time after infusion. Upper left inset: region of electrode contact within the dorsal raphe nucleus. Upper right inset: typical waveform characteristic of presumed 5-HT neurons encountered during electrophysiological recordings. Ordinate scale unit = 1 mV; abscissa scale unit = 1 ms. (B) Local microinjection of URB597 into the medial prefrontal cortex significantly enhanced the firing rate of dorsal raphe 5-HT neurons relative to vehicle-treated rats (vehicle, n = 41 neurons; URB597, n = 38 neurons). Data are presented as mean firing rate (Hz) +/- SEM (n = 4-5 rats / treatment condition). * denotes significant differences at p < 0.05.