Sensitivity of rubrospinal neurons to excitatory amino acids in the rat red nucleus in vivo.
Responses of rubrospinal neurons (RSNs) to iontophoretic applications of L-glutamate (L-Glu), L-aspartate (L-Asp), quisqualate (Quis) and N-methyl-D-aspartate (NMDA) have been studied in the rat red nucleus (RN) in vivo. All agonists produced a dose-dependent increase of the firing rate and Quis was found to be the most efficient. The responses to NMDA and to a lesser extent to L-Asp were abolished by steady application of 2-amino-5-phosphonovalerate (2APV) whereas responses to Quis were unaffected and those to L-Glu poorly antagonized. On the other hand, NMDA-mediated excitations were insensitive to steady application of 6,7-dinitroquinoxaline-2,3-dione (DNQX) which abolished responses to Quis and to a lesser extent to L-Glu while those to L-Asp were less affected. These results show the presence of both NMDA and non-NMDA receptors on RSNs in the rat. A specific localization of the NMDA receptors on distal dendrites of these neurons is suggested.
Laboratoire de physiologie de la motricité, CNRS UA 385, Paris, France.
J M
JM
Billard
H
H
Daniel
R
R
Pumain
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000344:Afferent Pathways / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002415:Cats / Q000502:physiology; D002531:Cerebellum / Q000033:anatomy & histology / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D007478:Iontophoresis; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011810:Quinoxalines / Q000494:pharmacology; D016318:Quisqualic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats / Q000502:physiology*; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology; D012012:Red Nucleus / Q000187:drug effects* / Q000502:physiology; D013045:Species Specificity
D015763:2-Amino-5-phosphonovalerate; D001224:Aspartic Acid; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates; D018698:Glutamic Acid; D016202:N-Methylaspartate; D011810:Quinoxalines; D016318:Quisqualic Acid; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; C056723:FG 9041