Decreased membrane fluidity of lymphocytes from patients with juvenile neuronal ceroid-lipofuscinosis.

The storage material in neuronal ceroid-lipofuscinoses (NCL) apparently contains breakdown products of membrane lipids. The storage could be due to an unknown enzyme deficiency in the degradation of lipids or to an alteration of the lipid substrate within the plasma membrane. We investigated the membrane fluidity of intact lymphocytes in juvenile NCL (McKusick no. 20420) by steady-state fluorescence polarization. Fluorescent probes used were diphenylhexatriene (DPH), trimethylammonium-DPH (TMA-DPH), and a set of n-(9-anthroyloxy) fatty acids. Membrane fluidity was decreased in NCl (n = 12) vs. control lymphocytes when measured with the labels DPH, TMA-DPH, 6-, 7-(9-anthroyloxy) stearic acid, and 16- (9-anthroyloxy) palmitic acid (P less than 0.05). In order to check for the influence of anticonvulsants on membrane fluidity, we investigated 17 epileptic patients (without NCL) treated with anticonvulsants. Membrane fluidity was increased in these patients when measured with DPH and with the anthroyloxy probes. Our results indicate a decreased fluidity of the outer membrane leaflet in NCL lymphocytes which is independent of the effect of anticonvulsants.