Adenosine A 2 stimulation of tyrosine hydroxylase in rat striatal minces is reversed by dopamine D 2 autoreceptor activation

Abstract

The adenosine agonist, 2-chloroadenosine, stimulated tyrosine hydroxylase activity in rat striatal minces; this effect was attenuated by activation of dopamine (DA) D 2 autoreceptors with N-n-propylnorapomorphine and antagonized by theopylline. Forskolin and 8-bromo-cAMP also increased tyrosine hydroxylase activity and their effects were not altered by 2-chloroadenosine. D 1, α, β and 5-HT agonists did not affect tyrosine hydroxylase activity. Evidently, A 2 receptors on DA nerve terminals stimulate striatal DA synthesis and this effect is negatively modulated by D 2 autoreceptors, probably via changes in intracellular cAMP levels.