Stereoselectivity of extraneuronal uptake of catecholamines in rabbit aorta.

In incubated rabbit aorta, stereoselective preference of (-)isoprenaline and (-)adrenaline, but not of (-)noradrenaline, was observed with respect to extraneuronal (corticosterone-sensitive) catecholamine accumulation at relatively low amine concentrations. The ranking order (isoprenaline greater than adrenaline greater than noradrenaline) and the degree of stereoselectivity were similar to those described for the perfused rat heart. Thus, stereoselectivity of the carrier-mediated extraneuronal uptake process is demonstrable for different species and under conditions of incubation as well as of perfusion. On the other hand, amine distribution into the tissue that is linked neither to uptake2 nor to uptake1 (but which might be rather important under incubation conditions) showed no stereoselectivity in rabbit aorta.