Occurrence of dentate granule cell LTP without proximal dendritic Ca2+ increase.
We investigated activity-dependent calcium increases in proximal dendrites of dentate granule cells in the rat hippocampus, and its relationship with induction of LTP at perforant path synapses (PP-synapses). LTP was induced at PP-synapses by high-frequency stimulation (HFS; 100 Hz for 0.4 s), and the same HFS evoked a dendritic calcium increase in the proximal dendrite. However, bath-application of the L-type voltage-dependent calcium channel (VDCC) blocker nimodipine noticeably reduced this calcium increase without abolishing induction of LTP. This calcium increase mediated by high-threshold VDCCs is likely to be evoked by action potentials. LTP induction at PP-synapses is hence suggested to be independent of action potential-induced calcium increases in the proximal dendrite.
Hashimoto
K
K
Department of Integrative Brain Science, Kyoto University Graduate School of Medicine, Japan.
Isomura
Y
Y
Kato
N
N
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism / Q000502:physiology*; D018891:Dentate Gyrus / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar
D002118:Calcium