Affordable Access

Frequency-dependent requirement for calcium store-operated mechanisms in induction of homosynaptic long-term depression at hippocampus CA1 synapses.

Authors
  • Nakano, Makoto
  • Yamada, Shin-ichiro
  • Udagawa, Rie
  • Kato, Nobuo
Type
Published Article
Journal
The European journal of neuroscience
Publication Date
May 01, 2004
Volume
19
Issue
10
Pages
2881–2887
Identifiers
PMID: 15147321
Source
Medline
License
Unknown

Abstract

For induction of long-term depression (LTD), mechanisms dependent on N-methyl-D-aspartate receptors (NMDARs) and on intracellular calcium stores have been separately known. How these two mechanisms coexist at the same synapses is not clear. Here, induction of LTD at hippocampal Schaffer collateral-to-CA1 pyramidal cell synapses was shown to depend on NMDARs throughout the theoretically predicted activation range for LTD induction. With stimulation at 1 Hz, the largest LTD was induced in a store-independent manner. With stimulation at 0.5 and 2.0 Hz the induced LTD was much smaller, and dependence on calcium stores appeared. Under caffeine application, an enlarged LTD was induced with 0.5 Hz stimulation. Postsynaptic blockade of ryanodine receptors prevented this caffeine-induced enhancement of LTD. It is therefore suggested that calcium release from calcium stores facilitated by caffeine contributed to the LTD enhancement, and that the caffeine effect was exerted on the postsynaptic side. Induction of this enhanced LTD was resistant to NMDAR blockade. We thus propose that the store-dependent mechanism for LTD induction is dormant at the centre of the theoretically predicted activation range for LTD induction, but operates at the fringes of this activation range, with its contribution more emphasized when ample calcium release occurs.

Report this publication

Statistics

Seen <100 times