[Functional changes in the synaptic membrane during in vitro interaction with bilirubin and serum albumin]

A decrease in total activity of ATPase and in specific activity of Na+,K+-ATPase as well as less rapid and distinct decrease in specific activity of acetylcholinesterase were observed in synaptosomal membrane after binding of bilirubin in vitro. Irradiation with blue light of the bilirubin-containing membrane particles caused a more distinct decrease in activity of these enzymes. Blood serum albumin, added to the suspension of bilirubin-containing particles of synaptosomal membrane, affected significantly the alterations in activity of membrane-bound enzymes caused by the irradiation. Character of the effect depended on pH of the medium and presence of organophilic ligands in blood serum albumin molecule.