Indirect adrenergic effect of compound 48/80 in cat cerebral arteries

Compound 48/80 evoked an increase in the spontaneous tritium release from cat cerebral arteries prelabelled with 3H-NA. This increase was abolished after cervical gangliectomy, external calcium removal or in the presence of colchicine. Cocaine brought about an enhancement in the release of radioactivity elicited by compound 48/80 while diphenhydramine did not affect it. These results suggest that compound 48/80 has an indirect adrenergic effect in cat cerebral arteries which is not mediated by the release of histamine from mast cells.