Effect of Monase and Related Compounds on Uptake of 5-Hydroxytryptamine by Platelets

Monase indole-3(2-aminobu-tyl) acetate, a monoamine oxidase inhibitor, and 8 other structurally related compounds with different substitutions on the indole ring and amine side chain inhibited 5-HT uptake by platelets, degree of inhibition being directly related to concentration of inhibitor without particular relation to structure. C¹⁴-Mon-ase which differs from 5-HT by the absence of a hydroxyl group in position 5 of the indole ring and by the presence of a different side chain, was concentrated only slightly by platelets. It was concluded that the structural specificity for 5-HT uptake is largely determined by the hydroxyl group at position 5 of the indole ring.