Transfer and Storage of Biogenic Monoamines in Subcellular Organelles of Blood Platelets

Abstract

Publisher Summary In isolated 5-hydroxytryptamine (5HT) organelles, the 5HT content is very high in relation to the relatively low solubility of an amine under physiological conditions. Organelles possess discriminating properties with regard to the uptake of various monoamines. 5HT and dopamine enter the organelles more readily than tryptamine, tyramine, and histamine. The uptake of 5HT is not influenced by glucose, ouabain, and metabolic inhibitors. The discriminating properties of isolated 5HT organelles concerning the uptake of aromatic monoamines are not connected with a mechanism dependent on metabolic energy. They are rather due to the physico-chemical qualities of the amines and organelles that influence the extra-intravesicular distribution of the amines, their penetration through the membrane of the organelles, and their binding to intravesicular constituents. These physico-chemical properties may be of importance especially for the formation of complexes between the amines and adenosine triphosphate (ATP) within the organelles.