Motor activity induced by disinhibition of the primary motor cortex of the rat is blocked by a non-NMDA glutamate receptor antagonist.
Application of a GABAA (gamma-aminobutyric acid-A) receptor antagonist through a microdialysis probe into the forelimb primary motor cortex of ketamine-anesthetized rats induced electromyographic activity in the contralateral forelimb. This activity consisted of spontaneous forelimb movements with a frequency of 0.8 +/- 0.2 Hz. The motor activity induced by GABAA receptor blockade was suppressed by application through the dialysis probe of a non-NMDA (N-methyl-D-aspartate) receptor antagonist, but not by an NMDA receptor antagonist. Glutamate eliminated the blocking effect of the non-NMDA receptor antagonist upon GABAA receptor blockade mediated activity. In conclusion, the results show that an excitatory input to the motor cortical output is mediated through a non-NMDA receptor, therefore the effects of cortical disinhibition may be controlled by non-NMDA receptors.
Castro-Alamancos
M A
MA
Cajal Institute, Madrid, Spain.
Borrell
J
J
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D001931:Brain Mapping; D003956:Dialysis; D004576:Electromyography; D058787:GABA-A Receptor Antagonists; D008297:Male; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000187:drug effects
D058787:GABA-A Receptor Antagonists; D011810:Quinoxalines; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D001640:Bicuculline