Asymmetric antagonistic effects of an inhalation anesthetic and high pressure on the phase transition temperature of dipalmitoyl phosphatidic acid bilayers.

The phase transition temperature (Tt) of dipalmitoyl phosphatidic acid multilamellar liposomes is depressed 10 degrees C by the inhalation anesthetic methoxyflurane at a concentration of 100 mmol/mol lipid. Application of 100 atm of helium pressure to pure phosphatidic acid liposomes increased Tt only 1.5 degrees C. However, application of 100 atm helium pressure to dipalmitoyl phosphatidic acid lipsomes containing 100 mmol methoxyflurane/mol lipid almost completely antagonized the effect of the anesthetic. A non-linear pressure effect is observed. In a previous study, a concentration of 60 mmol methoxyflurane/mol dipalmitoyl phosphatidylcholine depressed Tt only 1.5 degrees C, exhibiting a linear pressure effect. The completely different behavior in the charged membrane is best explained by extrusion of the anesthetic from the lipid phase.

[1]  K. Jacobson,et al.  Effects of local anesthetics on membrane properties. I. Changes in the fluidity of phospholipid bilayers. , 1975, Biochimica et biophysica acta.

[2]  H. Mcconnell,et al.  The fraction of the lipid in a biological membrane that is in a fluid state: a spin label assay. , 1972, Biochemical and biophysical research communications.

[3]  J. Trudell,et al.  Pressure-induced elevation of phase transition temperature in dipalmitoylphosphatidylcholine bilayers. An electron spin resonance measurement of the enthalpy of phase transition. , 1974, Biochimica et biophysica acta.

[4]  J. Vanderkooi,et al.  Interaction of general anesthetics with phospholipid vesicles and biological membranes. , 1977, Biochimica et biophysica acta.

[5]  E. Eger,et al.  Tolerance of mice to nitrous oxide. , 1979, The Journal of pharmacology and experimental therapeutics.

[6]  H. Galla,et al.  Cooperative lipid-protein interaction. Effect of pH and ionic strength on polymyxin binding to phosphatidic acid membranes. , 1979, Biochimica et biophysica acta.

[7]  H. Galla,et al.  Binding of polylysine to charged bilayer membranes: molecular organization of a lipid.peptide complex. , 1978, Biochimica et biophysica acta.

[8]  E. Sackmann,et al.  Polymorphism of phospholipid monolayers , 1978 .

[9]  K. Miller,et al.  The opposing effects of pressure and general anaesthetics on the cation permeability of liposomes of varying lipid composition. , 1973, Biochimica et biophysica acta.

[10]  A. Macdonald.  A dilatometric investigation of the effects of general anaesthetics, alcohols and hydrostatic pressure on the phase transition in smectic mesophases of dipalmitoyl phosphatidylcholine. , 1978, Biochimica et biophysica acta.

[11]  J. Trudell,et al.  Pressure Reversal of Anesthesia: The Extent of Small-molecule Exclusion from Spin-labeled Phospholipid Model Membranes , 1973, Anesthesiology.