Electrophysiological actions of luteinizing hormone-releasing hormone: intracellular studies in the rat hippocampal slice preparation.

The electrophysiological effects of luteinizing hormone-releasing hormone (LHRH) on CA1 pyramidal cells were investigated utilizing intracellular recordings from the in vitro rat hippocampal slice preparation. Bath application of LHRH (10(-7) - 10(-12) M) resulted in several changes in the electrophysiological properties of CA1 neurons. LHRH induced a long-lasting depolarization associated with increased input resistance, a decrease in the afterhyperpolarization (AHP) following a train of action potentials, and a reduction in accommodation of repetitive cell discharge. These effects were blocked by the synthetic LHRH antagonist [Ac-delta-Pro1,pCl-D-Phe2,D-Trp3,6]-LHRH. These findings provide electrophysiological evidence for the role of LHRH as a neurotransmitter/neuromodulator in the hippocampus.