Increased sleep time in the offspring of caffeine-treated dams from two inbred strains of mice

Dams from two inbred strains of mice (C57BR and BALB/c) were treated with caffeine in solution in their drinking water during gestation. Doses of caffeine used corresponded to about 60, 80 or 100 mg/kg/day; controls received tap water. The offspring (as adults) revealed a significantly increased sleep time following caffeine treatment, but primarily as slow wave sleep in the males of the BALB/c strain and paradoxical sleep in the females of the C57BR strain. BALB/c females and C57BR males were relatively unaffected. These results, and in particular the sex differences, are discussed in terms of a possible central site of action of caffeine.