Membrane Studies in Huntington's Disease: Steady State and Time‐Dependent Fluorescence Spectroscopy of Intact Lymphocytes

Abstract

A membrane abnormality, expressed in peripheral tissues such as the lymphocyte, may be present in Huntington''s disease (HD). Both steady state and time-dependent fluorescence spectroscopic methods were performed on lymphocytes from patients with HD and from age- and sex-matched controls. Lymphocyte membrane dynamics were studied, using fluorescence probes with known specificity for certain membrane areas. These probes included 4-phenylspiro(furan-2(3H)-1''-phthalan)-3,3''-dione (fluorescamine), which binds to surface membrane primary amines, 1,8-anilinonaphthalenesulfonate (1,8-ANS), which inserts at the aqueous-hydrocarbon interface and 12(9) anthroyl stearate (12(9)AS), which inserts deep in the hydrocarbon core. Steady state fluorescence studies, using fluorescamine, 1-8 ANS, or 12(9)AS, revealed no significant difference between intact HD and control lymphocytes. Time-dependent energy-transfer polarization studies for fluorescamine (tryptophan .fwdarw. fluorescamine) did reveal a slower time decay of I.perp./I.dblvert. for intact HD lymphocytes a compared with controls. This time-dependent difference may relate to alterations in translational (lateral) and angular mobilities of membrane donors (tryptophan) relative to acceptors (fluorescamine) in intact HD lymphocytes. Such observations support the concept of a membrane abnormality in HD.