Effects of dizocilpine-induced glutamatergic blockade in the nucleus accumbens septi on the plus maze test

Abstract

In previous studies, we have observed that specific N-methyl-d-Aspartic acid (NMDA) antagonists and non-NMDA antagonists injected within the nucleus accumbens septi (NAS) induced an anxiolytic-like effect in the plus maze test in rats. In the present study, the effect of intracanalicular blockade of NMDA receptors using dizocilpine in the plus maze was studied in male rats bilaterally cannulated NAS. Rats were divided into five groups that received either 1 μL injections of saline or dizocilpine (MK-801, [5R,10S]-[+]-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine) in different doses (0.5, 1, 2, or 4 μg) 15 min before testing. Time spent in the open arm increased under dizocilpine treatment with the two higher doses (2 and 4 μg, p<0.05), extreme arrivals were increased by the three higher doses (1 μg, p<0.05; 2 and 4 μg, p<0.01), and open arm entries by the three higher doses (1, 2, and 4 μg, p<0.05). A dose-effect relationship was observed in all cases. We conclude that dizocilpine-glutamatergic blockade in the accumbens lead to an anxiolytic-like effect and a behavioral disinhibition related to an increase in some motoric parameters, showing specific behavioral patterns.