Fig. 2.
A, Effect of iontophoretic pulses (50 nA, for 4 sec every 14 sec) of 8OH-DPAT (a 5HT1A receptor agonist) on a DRN neuron during W. The tonic activity of this neuron (1.8 Hz) is completely inhibited by 8OH-DPAT applications. This result strongly suggests that the recorded neuron is serotonergic. B, Photomicrograph illustrating a small PSB deposit localized in the center of the DRN on a frontal section counterstained with neutral red. The PSB was iontophoretically applied (−10 μA, 10 min) in the site in which neurons were recorded during the last day of experiments. It must be also noted that no lesion is visible in the DRN despite the multiple penetrations of the pipette assembly.