CNR ExploRA

Articolo in rivista, 2000, ENG, 10.1016/S0091-3057(00)00237-9

Caffeine-induced increases in the brain and plasma concentrations of neuroactive steroids in the rat

Concas A.; Porcu P.; Sogliano C.; Serra M.; Purdy R.H.; Biggio G.

Universita degli Studi di Cagliari; University of California, San Diego

The effects of caffeine, a naturally occurring stimulant, on the brain and plasma concentrations of neuroactive steroids were examined in the rat. A single intraperitoneal injection of caffeine induced dose- and time-dependent increases in the concentrations of pregnenolone, progesterone, and 3alpha- hydroxy-5alpha-pregnan-20-one (allopregnanolone) in the cerebral cortex. The increases were significant at a caffeine dose of 25 mg/kg and greatest (+188, +388, and +71%, respectively) at a dose of 100 mg/kg in rats killed 30 min after caffeine administration. Caffeine also increased the plasma concentrations of pregnenolone and progesterone with a dose-response relation similar to that observed in the brain, whereas the caffeine-induced increase in the plasma concentration of allopregnanolone was maximal at a dose of 50 mg/kg. Caffeine increased the plasma concentration of corticosterone, but it had no effect on the brain or plasma concentrations of 3alpha,21-dihydroxy-5alpha- pregnan-20-one and dehydroepiandrosterone. Moreover, the brain and plasma concentrations of pregnenolone, progesterone, and allopregnanolone were not affected by caffeine in adrenalectomized-orchiectomized rats. These results suggest that neuroactive steroids may modulate the stimulant and anxiogenic effects of caffeine. (C) 2000 Elsevier Science Inc.

Pharmacology, biochemistry and behavior 66 (1), pp. 39–45