Format

Send to

Choose Destination
See comment in PubMed Commons below
Neuropharmacology. 1993 Nov;32(11):1239-48.

The developmental onset of NMDA receptor-channel activity during neuronal migration.

Author information

  • 1Department of Physiology, Northwestern University Medical School, Chicago, IL 60611.

Abstract

Patch-clamp recordings of granule cells in thin slices of developing rat cerebellum maintained in vitro displayed spontaneous single-channel activity mediated via activation of N-methyl-D-aspartate (NMDA) receptors. The frequency of tonic single-channel activity was reversibly inhibited by the NMDA receptor/channel antagonists D-2-amino-5-phosphonovalerate (D-AP5), 7-chloro-kynurenate (7-Cl-Kynu) and MgCl2, potentiated by glycine, and unaffected by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or tetrodotoxin (TTX). Tonic channel activity was also reversibly inhibited by enzymatic degradation of endogenous glutamate by glutamate pyruvate transaminase, which did not affect the NMDA sensitivity of granule cells. Both the frequency of spontaneous channel activity and the NMDA sensitivity were low in premigratory cells of the external germinal layer (EGL), with large increases observed in migrating cells in the molecular layer (ML) and in postmigratory cells within the internal granule cell layer (GCL). Tonic channel activity was enhanced by the glutamate uptake inhibitor L-alpha-aminoadipate (L-alpha-AA), the degree of enhancement being greater in the EGL than the GCL. The results demonstrate that a dramatic increase in the tonic NMDA receptor-channel activity occurs during the stages of granule cell differentiation, migration and synaptogenesis, which is driven by endogenous glutamate release and regulated by NMDA receptor density and local glutamate uptake.

PMID:
7509049
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Loading ...
    Write to the Help Desk