Additive feature of long-term potentiation and phorbol ester-induced synaptic enhancement in the mossy fiber-CA3 synapse.
Application of phorbol esters, selective activators of protein kinase C (PKC), causes a long-lasting enhancement of synaptic transmission in the hippocampus. We examined the relationship between this phorbol ester-induced enhancement of synaptic transmission and long-term potentiation (LTP) quantitatively in the mossy fiber-CA3 synapse of the guinea pig hippocampus in vitro. Potentiating action of 0.5 microM phorbol 12,13-diacetate (PDAc) on synaptic transmission was almost unaffected by preceding tetanic stimuli which had caused a full development of LTP. Tetanic stimulation induced LTP even after synaptic transmission had been enhanced by 0.5 microM PDAc. Quantitative estimations revealed that PDAc-induced synaptic enhancement and LTP were simply additive to each other. The relation between LTP and PKC activation is discussed.
Kamiya
H
H
Department of Physiology, Faculty of Medicine, Kanazawa University, Japan.
Sawada
S
S
Yamamoto
C
C
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D006624:Hippocampus / Q000502:physiology*; D009412:Nerve Fibers / Q000502:physiology*; D010703:Phorbol Esters / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D010703:Phorbol Esters; C008874:phorbol-12,13-diacetate; D011493:Protein Kinase C