Metabotropic glutamate receptor agonists potentiate a slow afterdepolarization in CNS neurons.
We have previously reported that, in the rat dorsolateral septal nucleus (DLSN), metabotropic glutamate receptor (met-GluR) agonists evoked a slow depolarization accompanied by an increase in membrane conductance and burst firing. We have speculated that the burst firing elicited by met-GluR agonists may be due to activation or enhancement of a non-specific cation current, which exists in some DLSN neurons. Now we report that a slow afterdepolarization (sADP) mediated by a non-specific cation current was potentiated by both 1S,3R-ACPD and quisqualate. In addition, met-GluR agonists unmask a sADP in DLSN neurons which did not show a sADP under control conditions. Our data suggest that a non-specific cation current can be potentiated by activation of the met-GluR.
Zheng
F
F
Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston 77550.
Gallagher
J P
JP
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D005971:Glutamates / Q000378:metabolism*; D007051:Ibotenic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017470:Receptors, Glutamate / Q000187:drug effects / Q000502:physiology*
D005971:Glutamates; D011810:Quinoxalines; D017470:Receptors, Glutamate; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D007051:Ibotenic Acid; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D016318:Quisqualic Acid