Effects of CRH and LHRH on Rat Septo-Hippocampal Neurons

Abstract

Electrical activities of septum-diagonal band neurons (SD neurons) antidromically activated by electrical stimulation of the fimbria were recorded in urethane anesthetized male rats. The mean basal firing rate of antidromically identified SD neurons (2.3Hz) was not different from that of unidentified ones (2.2Hz). The mean latency of antidromic activation by the fimbria stimulation was 4.2 ms. Iontophoretically applied CRH and LHRH affected 60% and 40% of identified SD neurons, but only 19% and 13% of unidentified SD neurons, respectively. The ratio of response to no response to both peptides was significantly different in unidentified SD neurons from that in identified SD neurons. These results suggest that SD neurons mediate the effect of CRH and LHRH on hippocampal neurons.