Motor actions of excitatory amino acids and their antagonists within the rat ventromedial thalamic nucleus.
The present study investigates the role of excitatory amino acid receptors within the rat ventromedial thalamic nucleus (VM) for the mediation of motor behaviour. For this purpose changes of motility were monitored after microinjections of excitatory amino acids and of various excitatory amino acid antagonists into the VM. N-Methyl-D-aspartate (NMDA) and kainate (KA), but not quisqualate (QA), led to a dose-dependent increase of exploratory activity. A specific NMDA antagonist (-)-2-amino-7-phosphonoheptanoate (-)-AP7), preferential non-NMDA antagonists, 1-(p-chlorobenzoyl)-piperazine-2,3-dicarboxylate (pCB-PzDA) and gamma-D-glutamylaminomethylsulphonate (GAMS), and a broad spectrum antagonist, kynurenate (KYN), induced catalepsy in a dose-dependent manner. The catalepsy induced by (-)-AP7 was antagonized by NMDA, but not by KA, the pCB-PzDA-induced catalepsy was blocked by KA, but not by NMDA and the KYN-induced catalepsy was reversed by either NMDA or KA. These data point to a role of both NMDA and KA receptors within the VM for the regulation of motility.
D000596:Amino Acids / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002375:Catalepsy / Q000503:physiopathology; D005106:Exploratory Behavior / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface / Q000502:physiology*; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D013787:Thalamic Nuclei / Q000502:physiology*
D000596:Amino Acids; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D017981:Receptors, Neurotransmitter