Effects of thyrotropin-releasing hormone and a related analog, CNK-602A, on long-term potentiation in the mossy fiber-CA3 pathway of guinea pig hippocampal slices.
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.
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
K
K
Ishihara
H
H
Katsuki
A
A
Kawabata
M
M
Sasa
M
M
Satoh
S
S
Takaori
D000818:Animals; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005071:Evoked Potentials / Q000187:drug effects; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine / Q000494:pharmacology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology*; D012016:Reference Values; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013999:Timolol / Q000494:pharmacology*
C031926:montirelin; D013973:Thyrotropin-Releasing Hormone; D013999:Timolol; D016627:Oxidopamine; D004298:Dopamine; D009638:Norepinephrine