[Do anesthetics cause conformational changes in the majority of proteins in synaptic membranes?]

Cationic and neutral anesthetics at concentrations 1--10 mM increase SH-group accessibility to DTNB in the rat brain synaptic membranes, these effects for NEM-reactive groups being 5--10 times lower. High ionic strength depresses partially the influence of cationic but not neutral anesthetics in experiments with DTNB. Pronase treatment causing cleavage of all membrane proteins effects the anesthetic action in a small extent only. It is suggested that changes in the number of exposed SH-groups in the presence of anesthetics are related to modification of lipid phase rather than to conformational transitions in a majority of membrane proteins.