Properties of ionic transport through phospholipid-glycolipid artificial bilayers

The ionic transport properties of dioleoylphosphatidylcholine (DOPC) membranes containing various sphingolipids were studied. Particular attention was paid to membranes formed from beta-D-glucosylceramide (GlcCer) and DOPC. They showed a marked increase in ionic permeability (up to a factor 30 with respect to pure DOPC membranes), slight cation selectivity and almost linear behaviour of the current-voltage characteristic. Bilayers containing GlcCer showed a typical conductance decrease upon increasing the temperature. We suggest the formation of clusters containing GlcCer molecules in a solid-crystalline phase. The conductance increase might be due to ionic pathways through disordered boundary regions. An increase in the mechanical breakdown potential was observed in all membranes which contain sphingolipids.