[Effects of serotonin on the electric activity of paraventricular neurons of in vitro rat hypothalamic slices].

ABSTRACT

Hypothalamic slices were prepared with a vibratome. The spontaneous discharge of 46 paraventricular neurons was recorded by glass microelectrode from 20 such slices, and effects of serotonin on spontaneous discharge were observed. After perfusing the brain slices with artificial cerebro-spinal fluid containing serotonin (10(-6) mol/L) for 3 min, discharge rate of 16 units is significantly increased with latency 1.21 +/- 1.21 (mean + SD) min, this response is blocked by serotonin antagonist, cyproheptadine. The discharges of 3 units were decreased, but 25 units non-responsive. The experimental results suggest that about 1/3 of paraventricular neurons can be activated by topical application of serotonin via the activation of 5-HT receptors.