Effects of neonatal N-methyl-D-aspartate receptor blockade on social facilitation of feeding behavior in adult rats

Abstract

Glutamate and one of its ionotropic receptor subtypes, N-methyl-D-aspartate (NMDA) receptors, are essential for brain development after birth. Rats that underwent NMDA receptor blockade during the neonatal period have been validated as models of schizophrenia. Social facilitation, a phenomenon where an individual’s performance is promoted in the presence of others, reflects the ability to regulate behavior depending on social situations and is likely to be disrupted in schizophrenia. This study investigated the effects of neonatal treatment with MK-801, an NMDA receptor antagonist, on the social facilitation of feeding behavior in adult rats. Under noncompetitive conditions, SAL-treated control rats showed increased food intake when feeding with another rat, whereas MK-801-treated rats did not. Under competitive conditions, SAL-treated rats tended to feed more in the presence of a competitor compared to feeding alone. In contrast, MK-801-treated rats exhibited a significant reduction in food intake in the presence of a competitor. Thus, MK-801-treated rats demonstrated a lack of social facilitation under noncompetitive conditions and social inhibition under competitive conditions. These findings suggest that neonatal NMDA receptor blockade disrupts the ability of rats to regulate their behavior depending on their social situation. Our findings may provide new insights into the social deficits associated with schizophrenia and their underlying mechanisms.