Cocaine-sensitive uptake of sympathomimetic amines in nerve tissue

Abstract

The uptake of [³H]octopamine, [³H]norephedrine and [³H]phenylethanolamine in slices of cerebral cortex and heart of the mouse was investigated. Cocaine inhibited the uptake of octopamine but had no effect on that of the other two amines, whose uptake seems to be a pure physico-chemical partition between the tissue and the solution. Together with previous results, these indicate that the cocaine-sensitive uptake is linked with the hydroxyl groups in the benzene nucleus and particularly with that in the meta position. The results bear out the view that the potentiating effect of cocaine on the direct effect of sympathomimetic amines is due to inhibition of the uptake of the amines in sympathetic nerves, but they contradict the assumption that the antagonizing effect of cocaine on the indirect action of the amines is due to inhibition of the amine uptake.