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Abstract:
The fluorescence of 1-anilino-8-naphthalene sulfonate (ANS), dissolved in buffer, is enhanced by the narcotics ether and halothane.
Ether and halothane considerably reduce the quantum yield of ANS, bound to native and lipid-depleted sarcoplasmic vesicles. Obviously the effect of the anesthetics takes place at the same sites before and after delipidation.
The excitation spectrum of ANS, associated with the sarcoplasmic membranes, is resolved by halothane into at least two maxima with a new separate maximum at 394 nm. The emission spectrum is not influenced.
The narcotics are only able to influence the fluorescence of those ANS molecules which can be displaced by oleic acid, a noncompetitive inhibitor of the interaction of the dye with the membranes of native and lipid-depleted vesicles.
Higher homologues of diethylether did not influence the fluorescence. Fluorescence quenching by ether and halothane is enhanced with rising temperatures. The polarisation of the fluorescence of membrane-bound ANS is enhanced by halothane.
The intrinsic fluorescence of native and lipid-depleted vesicles is considerably decreased by halothane, hardly influenced by ether. Concentrations of 2.2 M sucrose completely abolish the fluorescence quenching by the narcotics.
All effects produced by ether and halothane are reversible.
