Accumulation of norepinephrine by macrophages and relationships to known uptake processes.

Incubation of mouse peritoneal macrophages with l-[3H]norepinephrine resulted in an apparent multiphasic accumulation of the catecholamine by the cells. Low temperature did and iodoacetate did not inhibit uptake. Part of the accumulation followed saturation kinetics; cocaine, metanephrine and phenoxybenzamine did not inhibit the observed uptake. On this basis, it was concluded that the uptake process or combination of processes could not be classified solely as uptake1, uptake2 or simple diffusion However, similarities between norepinephrine accumulation by macrophages and that by other extraneuronal tissues do exist. This, along with previous morphological data, suggests that the macrophage uptake may typify a component of extraneuronal accumulation of norepinephrine and that this component may, in part, result from a nonspecific membrane perturbation by norepinephrine.