Alpha-receptor-mediated modulation of 3H-noradrenaline release from rat brain cortex synaptosomes

Summary The effects of oxymetazoline and noradrenaline (in the presence of desipramine) on the release of ³H-noradrenaline from rat brain cortex synaptosomes were studied using a superfusion technique. Both drugs (at 1M concentrations) were found to reduce the depolarization-induced (15 mM K⁺) release of ³H-noradrenaline. The release-modulating effect of noradrenaline was antagonized by phentolamine and yohimbine.The data provide direct evidence for the hypothesis that -receptors modulating the release of noradrenaline are localized on varicosities of central noradrenergic neurones.