Differential alteration of hippocampal synaptic strength induced by pituitary adenylate cyclase activating polypeptide-38 (PACAP-38).
We investigated the effect of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on synaptic transmission in rat hippocampal slices using extracellular recordings. Brief bath application of PACAP-38 induced a long-lasting depression of transmission at the Schaffer collateral-CA1 synapse while at the same time causing enhancement of the perforant path-granule cell synapse in the dentate gyrus. Depression at the CA1 synapse was not occluded by low frequency-induced long-term depression (LTD), nor was enhancement at the granule cell synapse blocked by previous high frequency-induced long-term potentiation (LTP). Both actions of PACAP-38 could be elicited in the presence of an N-methyl-D-aspartate (NMDA) receptor antagonist, or in the presence of inhibitors of cyclic AMP- or Ca2+-dependent protein kinases, suggesting a novel mechanism of synaptic modulation.
Kondo
T
T
Supermolecular Science Division, Electrotechnical Laboratory, Umezono, Tsukuba, Japan. kondo@etl.go.jp
Tominaga
T
T
Ichikawa
M
M
Iijima
T
T
D000818:Animals; D018891:Dentate Gyrus / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009473:Neuronal Plasticity / Q000187:drug effects; D009479:Neuropeptides / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D047428:Protein Kinase Inhibitors; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013569:Synapses / Q000187:drug effects*; D013570:Synaptic Membranes / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D047428:Protein Kinase Inhibitors; D016194:Receptors, N-Methyl-D-Aspartate