Effect of noradrenaline on its own internal liberation from cortex synaptosomes in the rat]

Norepinephrine (NE) uptake velocity in rat cerebral cortex synaptosomes does not depend on internal NE contents: continuous exchange occurs. NE enhances spontaneous release and inhibits release elicited by KCl. Phenylephrine an a agonist, produces the same effect. Phentolamine, an a antagonist, did not modified the spontaneous release but enhanced release elicited by KCl 25 mM.