Ishihara K, Katsuki H, Kawabata A, Sasa M, Satoh M, Takaori S
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
Brain Res. 1991 Jul 19;554(1-2):203-8. doi: 10.1016/0006-8993(91)90190-7.
The effects of thyrotropin-releasing hormone (TRH) and a related analog, CNK-602A, that induces the release of catecholamines, on long-term potentiation (LTP) of the population spike in mossy fiber-CA3 pathways were investigated in guinea pig hippocampal slices. TRH augmented LTP of the population spike at concentrations of 10(-6)-10(-5) M. CNK-602A also augmented LTP at concentrations of 10(-6)-10(-5) M in a dose-dependent manner. LTP in slices of the hippocampus obtained from animals given 6-hydroxydopamine (6-OHDA) intraventricularly was significantly lower than that in non-treated animals. However, both TRH and CNK-602A (10(-6) M) augmented LTP in slices from 6-OHDA-treated animals. These findings suggest that TRH and CNK-602A augment LTP in the mossy fiber-CA3 pathway without activating noradrenergic and/or dopaminergic fibers.
