EVALUATION OF AGE DIFFERENCES IN LOCOMOTOR ACTIVITY FOLLOWING PSYCHOSTIMULANT ADMINISTRATION IN ADOLESCENT VERSUS ADULT MICE BY

In humans, the brain continues to develop over the course of adolescence. One implication is that drugs of abuse are likely to impact adolescents differently than adults. Rodent literature has added credibility to this idea. Following administration of an equivalent dose of psychostimulant (e.g. cocaine, amphetamine, methamphetamine), adolescent rodents are commonly observed to locomotor stimulate to a lesser magnitude than that of adults. However, recently conflicting reports have been published showing adolescents to stimulate equally or greater than adults. The cause for variability in the literature is unclear, but may be a result of genetic differences between subjects or other dissimilarities in experimental design. Therefore, in Chapter 2 adolescent (postnatal day 30) and adult (postnatal day 65) mice of both sexes from four different inbred strains (C57BL/6J, BALB/cByJ, DBA/2J, FVB/NJ) were screened for differences in locomotor stimulation following cocaine. The greatest difference in stimulation between age groups was observed in C57BL/6J, but BALB/cByJ and female FVB/NJ mice also showed attenuated stimulation in adolescents as compared to adults. Since locomotor stimulation differences were greatest in C57BL/6J mice, they were used in all subsequent chapters. Chapte