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Desensitization of group I metabotropic glutamate receptors in rat sympathetic neurons.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kammermeier, Paul J. Ikeda, Stephen R. |
| Copyright Year | 2002 |
| Abstract | Desensitization of heterologously expressed metabotropic glutamate receptor 5a (mGluR5a) was examined in rat sympathetic neurons. Calcium currents in cells expressing mGluR5a exhibited substantial inhibition in response to glutamate exposure. In the continued presence of glutamate, inhibition attenuated rapidly over the course of about a minute. Desensitization was eliminated when a nonhydrolyzable ATP analogue was substituted for ATP in the pipette solution, suggesting that desensitization was mediated by a phosphorylation event. Next, pharmacological agents were used to investigate the nature of the kinase involved in desensitization. Desensitization was sensitive to the nonspecific kinase inhibitor, staurosporine, but not H-7, another nonspecific kinase inhibitor. Inhibitors of myosin light chain kinase and calmodulin-dependent kinase were without effect on desensitization. However, desensitization was sensitive to the protein kinase C inhibitor bisindolymaleimide. In contrast, Gö6976, a selective inhibitor of conventional protein kinase C isoforms, was without effect. In addition, desensitization persisted in the presence of 10 mM intracellular bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid, a fast Ca(2+) chelator. Finally, overexpression of wild-type calmodulin, which can bind mGluR5 and inhibit phosphorylation, did not alter mGluR desensitization. Two Ca(2+)-binding-deficient calmodulin mutants were also without effect. These data indicate a role for nonconventional protein kinase C isoforms as a mediator of mGluR5 desensitization and that the phosphorylation of mGluR5a that competes with calmodulin binding does not mediate desensitization. |
| Starting Page | 503 |
| Ending Page | 513 |
| Page Count | 11 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://jn.physiology.org/content/jn/87/4/1669.full.pdf |
| PubMed reference number | 11929888v1 |
| Volume Number | 87 |
| Issue Number | 4 |
| Journal | Journal of neurophysiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Adenosine Triphosphate Analog Calcium Calmodulin 1 Glutamic Acid Maxillary right first premolar abutment Mediator brand of benfluorex hydrochloride Metabotropic Glutamate Receptor 5a Pharmacology Pipette (physical object) Protein Isoforms Protein Kinase C Protein Kinases Receptor Desensitization Receptors, Metabotropic Glutamate Staurosporine Thioctic Acid hypersensitivity desensitization mutant |
| Content Type | Text |
| Resource Type | Article |
