The effect of apomorphine and haloperidol on the RNA content of brain structures of the rat.

At a dose of 0.5 mg/kg, apomorphine caused an increase of the RNA content of the septal nucleus of rats (n. medialis + n. lateralis + n. accumbens); after 2.5 mg/kg this effect became more marked and, in addition, there was an increase of RNA in the caudate nucleus. All effects were antagonized by 0.5 mg/kg of haloperidol. These data suggest that apomorphine acts, at different dose levels, on different sites of the brain. This might be related to the also different behavioral effects of apomorphine at those two dose levels. Haloperidol on its own caused a fall of RNA in the amygdaloid nucleus which was not counteracted by any of the two doses of apomorphine. Neither drug had any influence on hypothalamic RNA concentration.