Effects of forskolin on spontaneous behavior, rectal temperature and brain cAMP levels of rats: interaction with rolipram.

The effects of systemically administered forskolin, a direct activator of the catalytic subunit of adenylate cyclase, on locomotor activity, rectal temperature and the incidence of grooming and head twitches were studied in rats. Forskolin, 0.1-25 mg/kg, decreased locomotor activity and lowered rectal temperature. The incidence of grooming and head twitches increased dose-dependently after forskolin, 6.25 25 mg/kg. The combination of a threshold dose of forskolin with a threshold dose of the cAMP-selective phosphodiesterase (PDE) inhibitor rolipram resulted in a marked, statistically significant enhancement of the behavioral, hypothermic and brain cAMP elevating effect. The present findings support the assumption that enhanced brain cAMP availability is associated with a characteristic behavioral syndrome in rats as was previously shown with dibutyryl cAMP or neurotropic cAMP-selective PDE inhibitors like rolipram. Ro 20-1724 or ICI 63 147.