Fig. 4.

Effect of an iontophoretic application of bicuculline on a DRN serotonergic cell during PS. In control conditions, the DRN neuron does not discharge during PS (100–120 sec). Thirty seconds after the onset of the bicuculline application (70 nA, 42 sec), the neuron increased its discharge rate to a mean frequency of 3.6 Hz. The effect lasted 43 sec and disappeared 31 sec after the end of the bicuculline application. Note that the PS period is not disrupted by the application of bicuculline.