Influence of amphetamine-induced changes in the behavior of adult "aunts" on development and long term behavioral patterns of rats.

Infant rats of the Wistar strain were kept either with their mother or with both the mother and the "aunt"--an adult virgin female during the suckling period. One group of aunts was injected regularly with amphetamine in the dose of 3 mg/kg b.w. (the AA group), another group with saline (the SA group). Control (CO) pups were reared by their mother only. Both acute and long term consequences of aunt-rearing on behavioral development and growth rate were observed. On Days 25 and 28 the SA pups displayed an increased exploratory activity level and more contacts with the litter-mate in the test of paired interactions when compared with both the AA and CO groups. The lowest frequency of exploratory, of manipulatory and social activities were recorded for the AA pups. In adulthood, both the aunt-reared groups of male rats exhibited higher activity level in a novel environment than the CO males. However, while in the CO and the SA males the activity level tended to habituate over the repeated tests, in the AA it persisted on a high level. The difference among females was not significant. Growth rate was retarded in the AA male and female rats.