Enhancement in switching motor patterns following local application of the glutamate agonist AMPA into the cat caudate nucleus.
The effect of caudate nucleus (CN)-injections of the glutamate agonist DL-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA), viz. an agonist of quisqualate receptors, on switching behaviour was investigated: first, cats had to switch from hanging with the forepaws on the bar to climbing on the bar; then, they had to switch to walking; finally, they had to switch to jumping off the bar. AMPA induced limb deficits, i.e. unilateral incorrect or absent placing of the fore- and/or hindlimb, in part of the tested cats; in the remainder of the tested animals AMPA reduced climbing time. Limb deficits were prevented by the broad-spectrum glutamate antagonist kynurenic acid (KYN) and by the selective NMDA antagonist D-2-amino-7-phosphono-heptanoate. In all cats AMPA increased the number of head movements as well as that of walking-restarts. These effects were counteracted only by KYN. These data show that part of the AMPA-induced effects were selectively mediated by quisqualate receptors. The present data are discussed in view of the role of the caudate nucleus in switching behaviour.
Jaspers
R M
RM
Psychoneuropharmacological Research Unit, University of Nijmegen, The Netherlands.
de Vries
T J
TJ
Cools
A R
AR
D000818:Animals; D001931:Brain Mapping; D002415:Cats; D002421:Caudate Nucleus / Q000187:drug effects*; D004292:Dominance, Cerebral / Q000187:drug effects; D005552:Forelimb / Q000294:innervation; D006614:Hindlimb / Q000294:innervation; D007051:Ibotenic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D008124:Locomotion / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009048:Motor Skills / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D010080:Oxazoles / Q000494:pharmacology*; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D010080:Oxazoles; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D007051:Ibotenic Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid