Effect of urapidil on rat brain catecholamine synthesis.
The effects of urapidil, a clinically effective antihypertensive drug, on the in-vivo rate of synthesis of rat brain noradrenaline (NA) and dopamine (DA) was determined. A significant dose-dependent increase in dopa concentration by urapidil after dopa decarboxylase inhibition by NSD 1015 was observed in brain stem (3-30 mg kg-1 i.p.) and striatum (10-30 mg kg-1 i.p.), indicating increased NA and DA turnover, respectively, most probably a result of central blockade of brainstem alpha 1-adrenergic and striatal DA receptors. These results indicate that urapidil may possibly exert its central hypotensive action in part by a reduced influence on brain stem NA, thus reducing central sympathetic outflow.
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002395:Catecholamines / Q000096:biosynthesis*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D008297:Male; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats
D002395:Catecholamines; D010879:Piperazines; D004295:Dihydroxyphenylalanine; C015568:urapidil