Effects of AMPA/kainate receptor blockade on responses to dopamine receptor agonists in the core and shell of the rat nucleus accumbens.
The present experiments were conducted to investigate effects of alpha-amino-3-hydroxy-5-methyl-4-isoxazoleprionic acid (AMPA)/kainate receptor blockade (CNQX, NBQX) on locomotor responses to D2/3 (7-OH-DPAT) and D1 [(+)-SKF 38393] dopamine receptor agonists in the nucleus accumbens (NAS) core and shell. CNQX (0.25-0.5 microgram) microinjected into the NAS core or shell did not affect baseline locomotor activity. 7-OH-DPAT (2.5-5 micrograms) decreased locomotor activity. Co-administration of CNQX (0.5 microgram) increased the effects of 7-OH-DPAT (5 micrograms) in the NAS core and shell. A similar increase was observed with NBQX (0.5 microgram) in the NAS shell. (+)-SKF 38393 (5 micrograms) into the NAS core and shell increased locomotor activity after 30 min; this effect was not altered by CNQX (0.5 microgram). As the D2/3 dopamine agonist (-)-quinpirole (2 micrograms) increased effects of (+)-SKF 38393 (5 micrograms) in NAS shell but not core, lack of site-selective effects of (+)-SKF-38393 and of 7-OH-DPAT within NAS is not attributable to drug diffusion. The previous observation that glutamate effects on locomotor activity depend on the relative involvement of D1 or D2/3 dopamine receptors in the NAS was based on the dopamine-depletion model. The present results demonstrate differential interactions of AMPA receptor blockade with dopamine agonists in "dopamine-intact" animals.
Choi
K H
KH
Department of Psychiatry, University of Alberta, Edmonton, Canada.
Zarandi
B
B
Todd
K G
KG
Biondo
A M
AM
Greenshaw
A J
AJ
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D018491:Dopamine Agonists / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors* / Q000502:physiology; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors* / Q000502:physiology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018491:Dopamine Agonists; D018691:Excitatory Amino Acid Antagonists; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D013764:Tetrahydronaphthalenes; C031349:7-hydroxy-2-N,N-dipropylaminotetralin