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Recent evidence suggests that 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-anilinonaphthalene sulfonate (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 leads to fluorescamine) did, however, reveal a slower time decay of (formula see text) for intact HD lymphocytes as 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.

Recent evidence suggests that a membrane abnormality may be present in Huntington's disease (HD), including peripheral tissues such as erythrocytes. Steady-state fluorescence spectroscopy was performed on intact erythrocytes from patients with HD and from normal age- and sex-matched controls. Fluorescent probes with known specificity for certain membrane areas were used to survey membrane dynamics; these probes included fluorescamine, which binds to primary amines on the cell surface, and both 12(9)-anthroyl stearate, 12(9)AS, and 2(9)-anthroyl stearate, 2(9)AS, which insert at different depths in the hydrocarbon core of membranes. In the intact HD erythrocyte, fluorescamine revealed decreased polarization, 12(9)AS showed increased polarization, and 2(9)AS showed no difference as compared to normal erythrocytes. These studies suggest that fluorescamine, attached to primary amines of the cell surface in intact HD erythrocytes, has increased rotational mobility whereas the anthroyl moiety of 12(9)AS in the hydrocarbon interior has decreased rotational mobility. These studies thus support the concept of a membrane abnormality in HD.