Alteration of the effects of caffeine by prenatal stress

We examined the effect of prenatal stress exposure on sensitivity to caffeine using behavioral and physiological measures. Pregnant rats were handled 5 minutes daily from the 14th to 21st day of gestation. Male offspring were tested when 60 days of age in a modified open field apparatus 30 and 90 minutes after injection with caffeine (0, 10, 30 mg/kg). Caffeine increased crossover frequency and duration at the 10 mg/kg dose. Rearing frequency and duration were increased by the 10 mg/kg dose while the 30 mg/kg dose was ineffective. Gnawing was increased by caffeine, especially 90 minutes postinjection. Headpoke activity was decreased by caffeine treatment. Caffeine had no effect on defecation and urination. Gnawing activity was increased by caffeine in prenatally nonstressed animals, but was depressed in prenatally stressed animals. Prenatal stress increased sensitivity to caffeine on corner activity and rearing. The other measures were not affected differentially by prenatal stress exposure. Rectal temperature was depressed 0.75 degrees C in both prenatally stressed and nonstressed animals, by the 30 mg/kg dose of caffeine. Thus, our results indicate that prenatal stress affects sensitivity to caffeine in the adult offspring. However, the long-term effects of prenatal stress exposure are dependent on the measures employed.