Interaction of phenothiazines and lower aliphatic alcohols with erythrocyte membranes: a scanning calorimetric study
Krishnan, K.S.; Brandts, J.F.
Molecular Pharmacology 16(1): 181-188
1979
ISSN/ISBN: 0026-895X PMID: 39242 Document Number: 141761
Human erythrocyte membranes at pH 7.4 in 310 imosm Na3PO4 buffer show several distinct endothermic transitions when studied by differential heat capacity calorimetry. Various tranquilizers in the phenothiazine family shift one of the major transitions, normally at 67.degree. C, down to about 60.degree. C when present at concentrations of 40 .mu.M or less. The lower aliphatic alcohols in dilute concentrations affect 2 of the transitions and at higher concentrations shift all the transitions down by temperatures as much as 30.degree. C. The concentrations of alcohols needed to cause similar effects decrease with increasing number of C atoms. The effect of alcohols and phenothiazines below 150 .mu.M can be reversed by washing the membranes in Na3PO4 buffer. The common effect of all these compounds at anesthetic concentrations seems to be mainly on one transition, which was tentatively identified as involving a lipid domain on the membrane previously shown to function in anion transport.