Effects of systemic administration of 0.1, 0.2, 0.5, and 1 mg/kg of MK-801 (arrow) on the efflux of 5-HT (a) and glutamate (b) in the mPFC. Data (mean±SEM) are expressed as percentage changes of the four basal pretreatment values. Number of animals is given in parentheses. The control group received one injection of saline (arrow). *p<0.05, **p<0.005, ***p<0.0005, Newman–Keuls test following ANOVA.