Preparation of Large Unilamellar Vesicles

We used large unilamellar vesicles
(LUVs) composed of a mixture of zwitterionic and negatively charged
lipids (DMPC and DMPS in 3:1 ratio) or the brain total lipid extract
(bTLE). Model membranes were prepared as described elsewhere.^{85 (link)} Briefly, appropriate aliquots of lipid stock
solutions in chloroform were dried by using a stream of dry nitrogen
and evaporated overnight under high vacuum to dryness in a round-bottomed
flask. Initially, multilamellar vesicles (MLVs) were obtained by hydrating
the lipid film with an appropriate amount of buffer (aCSF buffer 10
mM (pH 7.4) or MOPS buffer 10 mM and 100 mM NaCl (pH 7.4)) and dispersing
by vigorous stirring. MLVs were then extruded through polycarbonate
filters (pore size = 100 nm, Nuclepore, Pleasanton, CA) mounted in
a mini-extruder (Avestin, Ottawa, Canada) fitted with two 0.5 mL Hamilton
gastight syringes (Hamilton, Reno, NV) to obtain LUVs. Samples were
typically subjected to 23 passes through two filters in tandem and
as recommended elsewhere.^{86 (link)}