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Insulin Causes a Transient Tyrosine Phosphorylation of NR2A and NR2B NMDA Receptor Subunits in Rat Hippocampus
Author(s) -
Christie J. M.,
Wenthold R. J.,
Monaghan D. T.
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.721523.x
Subject(s) - nmda receptor , tyrosine phosphorylation , phosphorylation , hippocampal formation , long term potentiation , insulin , endocrinology , medicine , insulin receptor , tyrosine , biology , receptor , chemistry , microbiology and biotechnology , biochemistry , insulin resistance
NMDA receptors play a critical role in various aspects of CNS function. Hence, it is important to identify mechanisms that regulate NMDA receptor activity. We have shown previously that insulin rapidly potentiates NMDA receptor activity in both native and recombinant expression systems. Here we report that insulin causes a transient phosphorylation of NR2A and NR2B NMDA receptor subunits on tyrosine residues. Rat hippocampal slices were exposed to 1 μ M insulin for 20 and 60 min and then solubilized. NR2A and NR2B subunits were immunoprecipitated and probed for tyrosine phosphorylation. Insulin incubation of hippocampal slices for 20 min elicited an increase in tyrosine phosphorylation to 176 ± 16% (NR2A) and 203 ± 15% (NR2B) of control levels. In contrast, 60 min of insulin incubation did not alter NR2 tyrosine phosphorylation levels (NR2A: 85 ± 13% of control; NR2B: 93 ± 10% of control). Although the consequence of insulin‐stimulated tyrosine phosphorylation is unknown, it is possible that this site(s) is responsible for insulin potentiation of NMDA receptor activity. This possibility is consistent with our earlier finding that insulin potentiates hippocampal NMDA receptor activity after 20 min, but not after 60 min, of insulin exposure.