Parallel strain-dependent susceptibility to environmentally-induced stereotypies and stress-induced behavioral sensitization in mice.

Food restriction (9 days) promoted stereotyped behavior in drug-free mice of the DBA/2 (DBA), but not in those of the C57BL/6 (C57), inbred strain. Indeed, behavior presented by food-restricted mice of the DBA strain within the home cage was characterised by a very high response rate within a single response: cage cover climbing. Moreover, enhanced climbing in food-restricted mice of the DBA strain was also observed in a test designed to detect stereotypic effects of drugs in mice. Stereotypic behavior in DBA mice did not depend on nutritional status because: 1. No stereotypies were observed in DBA mice food-deprived for 15 h; 2. no strain-dependent differences in weight loss were observed; and 3. enhanced cage cover climbing was still evident in DBA mice following 24 h of free feeding. Finally, food-restricted DBA mice showed long-lasting sensitization to the locomotor effects of systemic amphetamine, indicating stress-induced behavioral sensitization in this strain of mice. By contrast, no sign of behavioral sensitization was observed in food-restricted mice of the C57 strain. These results indicate that restricted feeding promotes stereotyped behavior, as well as behavioral sensitization to amphetamine, in mice. Moreover, the observed parallelism between strain-dependent susceptibility to environmentally-induced stereotypies and behavioral sensitization supports the hypothesis that these phenomena share common neuro-biological bases.