Age-related differences in elevated plus maze behavior between adolescent and adult rats

Adolescence is a time of considerable transformations, often associated with increases in risk taking and novelty-seeking behaviors. Little is known of a possible age-dependent expression of anxiety-related behaviors in novel or potentially dangerous situations. The present study explored age differences in anxiogenic and anxiolytic stimuli between adolescent and adult Sprague-Dawley rats using the elevated plus maze (EPM). Data were compared across several experiments using factor analysis of multiple EPM measures. Under some circumstances, adolescents revealed a relatively low behavioral anxiety profile compared to adults, whereas in other situations results revealed the opposite pattern. Characteristics of the pretest circumstances altered considerably the nature of the conclusions reached regarding age-related changes in anxiogenic and anxiolytic stimuli. In general, anxiety measures in adolescents were less affected by variations in pretest conditions compared to the same variables in adults, suggesting possible adolescent immaturity of brain mechanisms involved in the regulation of anxiety.