Premium
Stimulation of N ‐methyl‐ d ‐aspartate receptors, AMPA receptors or metabotropic glutamate receptors leads to rapid internalization of AMPA receptors in cultured nucleus accumbens neurons
Author(s) -
Mangiavacchi Simona,
Wolf Marina E.
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2004.03511.x
Subject(s) - ampa receptor , cnqx , long term depression , metabotropic glutamate receptor , metabotropic glutamate receptor 1 , internalization , glutamate receptor , nmda receptor , chemistry , silent synapse , metabotropic glutamate receptor 5 , nucleus accumbens , metabotropic receptor , receptor , pharmacology , biology , microbiology and biotechnology , biochemistry
In hippocampus and other regions, α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA) receptors are inserted into synapses during long‐term potentiation and removed during long‐term depression. However, little is known about regulation of AMPA receptor trafficking in the nucleus accumbens (NAc), despite growing evidence that glutamate‐dependent forms of plasticity in the NAc contribute to drug addiction. Using postnatal rat NAc cultures and an immunocytochemical method that selectively detects newly internalized GluR1, we studied the regulation of AMPA receptor internalization in NAc neurons by glutamate agonists. Newly internalized GluR1 was detected during 15 or 30 min of incubation at room temperature, indicating a basal rate of GluR1 turnover. The rate of GluR1 internalization was increased by glutamate (50 µ m ) within 5 min of its addition. Glutamate‐induced GluR1 internalization was partially blocked by either an AMPA receptor antagonist (CNQX; 20 µ m ) or an N ‐methyl‐ d ‐aspartate (NMDA) receptor antagonist (APV; 50 µ m ). Both NMDA (50 µ m ) and AMPA (50 µ m ) increased GluR1 internalization in a Ca 2+ ‐dependent manner. The NMDA effect was blocked by APV while the AMPA effect was blocked by APV or CNQX. We interpret these findings to suggest that NMDA and AMPA ultimately trigger GluR1 internalization through the same NMDA receptor‐dependent pathway. The effect of glutamate was also partially blocked by the group 1 metabotropic glutamate receptor antagonist N ‐phenyl‐7‐(hydroxyimino)cyclopropa[b]chromen‐1a‐carboxamide (PHCCC; 50 µ m ), while the group 1 agonist 3,5‐dihydroxyphenylglycine (DHPG; 50 µ m ) stimulated GluR1 internalization. These data suggest that AMPA receptors on NAc neurons may be subject to rapid regulation of their surface expression in response to changes in the activity of glutamate inputs from cortical and limbic regions.