A role for calcineurin (protein phosphatase-2B) in the regulation of glutamate release.
Biochem Biophys Res Commun
; 212(2): 609-16, 1995 Jul 17.
Article
in En
| MEDLINE
| ID: mdl-7542882
ABSTRACT
Previous studies have shown that 4-aminopyridine (4AP) induced Ca-influx effects the release of glutamate from nerve terminals (synaptosomes) isolated from rat cerebral cortex. We now show that the Ca-dependent component of this release is potentiated by preincubation of the synaptosomes with the immunosuppressant, FK506, an inhibitor of protein phosphatase-2B (calcineurin). FK506 did not inhibit the Ca-independent release of glutamate from a cytosolic pool. Examination of the effect of FK506 on the influx of Ca elicited by 4AP indicated that inhibition of calcineurin activity resulted in an increase of voltage-dependent Ca-influx. Based on these results, we suggest that protein dephosphorylation effected by calcineurin may suppress voltage-dependent Ca-channel activity and in so doing inhibits evoked glutamate release. Activation of calcineurin produced by initial Ca-entry may represent a negative feedback to limit the activity of Ca-channels coupled to the release of glutamate.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Calmodulin-Binding Proteins
/
Cerebral Cortex
/
Phosphoprotein Phosphatases
/
Glutamic Acid
Limits:
Animals
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
1995
Document type:
Article
Affiliation country:
United kingdom
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA