Induction of locomotor activity by the glutamate antagonist DNQX injected into the ventral tegmental area.
DNQX, an antagonist of AMPA/kainate receptors, was injected into the ventral tegmental area (VTA) to test the hypothesis that AMPA/kainate receptors in this brain region might be involved in regulation of locomotor activity. Bilateral injection of 1 microgram DNQX into the VTA increased locomotor activity. In addition, unilateral injection of DNQX into this site produced contraversive turning, which was potentiated by coadministration of amphetamine (1 mg/kg, i.p.). These results suggest that a glutamatergic afferent to the VTA is tonically active in inhibiting locomotor activity. The locomotor stimulation produced by DNQX was not associated with a change in DOPAC/DA level in the nucleus accumbens or the striatum. However, the locomotor stimulation produced by DNQX was markedly attenuated following blockade of dopaminergic receptors by haloperidol (0.5 mg/kg, s.c.) or following dopamine depletion induced by reserpine plus alpha-methyl-para-tyrosine pretreatment. These results suggest that a basal activation of dopaminergic receptors is required for expression of the locomotor activity elicited by DNQX.
Dalia
A
A
Division of Pharmacology, College of Pharmacy, Ohio State University, Columbus 43210-1291, USA.
Uretsky
N J
NJ
Wallace
L J
LJ
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D011810:Quinoxalines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017557:Ventral Tegmental Area / Q000187:drug effects*
D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; C056723:FG 9041; D000661:Amphetamine