Adenosine receptor and beta-adrenoceptor stimulation increases noradrenaline synthesis in hippocampal synaptosomes.
The synthesis of noradrenaline was measured, using high-performance liquid chromatography with electrochemical detection, in synaptosomal fractions prepared from rat hippocampus. Noradrenaline synthesis is depressed by adenosine deaminase and the adenosine antagonist, 8-phenyltheophylline and stimulated by the adenosine agonist, 2-chloroadenosine. ?-Adrenoceptor stimulation also increases synthesis. The adenosine receptors and ?-adrenoceptors do not interact. Both receptor-mediated effects are distinct from, and additive with, the acceleration of synthesis by potassium-depolarisation. The results are compatible with an adenosine-receptor and ?-adrenoceptor stimulation of adenylate cyclase, leading to a cyclic AMP-mediated activation of tyrosine hydroxylase.
Birch
P J
PJ
University Laboratory of Physiology, Parks Road, Oxford, OX1 3PT, U.K.
Fillenz
M
M