CHANGES IN PLATELET 3-H-IMIPRAMINE BINDING - INFLUENCES OF PROTEIN-CONCENTRATION OF VARYING PROPORTIONS OF CYTOSOL OR INTACT PLATELETS AND DISPLACING AGENTS USED

Platelet 3-H imipramine binding exhibits considerable variation, both interindividually and between several groups. The aim of this study wa s to measure 3-H-imipramine binding, simultaneously in platelet membra nes vs. intact platelets and vs. cytosol or intracytosolic protein in order to determine their effect on B-max and K-d values. 3-H-imipramin e binding was carried out at different protein concentrations. Our res ults indicate that the affinity constant is heavily influenced by the presence of cytosol and intact platelets in membrane preparations. Fin ally, in this report we demonstrate a negative correlation between B-m ax and protein concentration. Only perfect analytical conditions will allow platelet 3-H-imipramine binding to be a biological marker for af fective disorders.