Effects of selective NMDA and non-NMDA blockade in the nucleus accumbens on the plus-maze test.
Effect of blocking N-methyl-D-aspartic acid (NMDA) and non-NMDA-glutamatergic receptors on performance in the plus-maze was studied in male rats bilaterally cannulated into the nucleus accumbens (Acc). Rats were divided into seven groups that received either 1 microl injections of saline, (+/-)2-amino-7-phosphonoheptanoic acid (AP-7, 0.2, 0.5, or 1 microg) or 2,3 dioxo-6-nitro-1,2,3,4,tetrahydrobenzo-(f)quinoxaline-7-sulphonamide disodium (NBQX, 0.2, 0.5, or 1 microg) 15 min before testing. Time spent in open arm, time per entry, end arrivals, open, closed, and total arm entries, relationship between open-, closed-, and total arm entries, rearing, face-, head-, and body grooming, and number of fecal boli were recorded. Time spent in the open arm increased under AP-7 (0.5 and 1 microg; P<.01) and NBQX (1 microg; P<.05) treatment, whereas time per entry was increased only with AP-7 (1 microg; P<.05). Open arm entries were increased by the intermediate doses of AP-7 (0.5 microg; P<.01) and NBQX (0.5 microg; P<.05); end arrivals were increased by the intermediate dose of AP-7 (0.5 microg/1 microl, P<.05). The frequency of rearing, grooming, and closed arm entries was not affected by the treatment. We conclude that NMDA and non-NMDA-glutamatergic blockade in the Acc lead to a behavioral disinhibition of cortical influences with the median doses, but that at higher doses the blockers have an anxiolytic-like effect.
Martínez
Gabriel
G
Laboratorio de Neurociencias y Psicología Experimental, Instituto de Medicina y Biología Experimental de Cuyo, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 7, 5500, Mendoza, Argentina.
Ropero
Claudia
C
Funes
Andrea
A
Flores
Erica
E
Blotta
Carina
C
Landa
Adriana I
AI
Gargiulo
Pascual A
PA
D000818:Animals; D001007:Anxiety / Q000523:psychology*; D003672:Defecation / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D013238:Stereotaxic Techniques
D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline