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THE EFFECT OF SOME GENERAL ANAESTHETICS ON THE SURFACE POTENTIAL OF LIPID MONOLAYERS
Author(s) -
BANGHAM A.D.,
MASON W.
Publication year - 1979
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1979.tb13674.x
Subject(s) - chemistry , monolayer , aqueous solution , adsorption , surface tension , aqueous two phase system , ethanol , bilayer , stereochemistry , analytical chemistry (journal) , chromatography , organic chemistry , membrane , thermodynamics , biochemistry , physics
1 This study sought to investigate the report by Ginsberg (1978) that 0.7 m ethanol brought about a +100 mV change (ΔΔV) in the surface potential of glyceryl monooleate (GMO) monolayers formed on KCl, although he predicted that a ΔΔV of −10 mV should have been found. 2 The effect of general anaesthetics such as n ‐alkyl alcohols and pentobarbitone on surface potential (ΔV) and surface tension (γ) of lipid monolayers formed on 145 m m KCl from either glyceryl monooleate (GMO) or phosphatidyl choline (PC) was examined with an Americium‐241 air electrode assembly (ΔV) and a platinized platinum dipping plate and force balance (γ). 3 It was found that, as predicted by Ginsberg (1978), addition of 0.7 m ethanol to the aqueous phase bathing either PC or GMO monolayers brings about a negative‐going change in interfacial potential (ΔΔV). 4 The magnitude of ΔΔV is dependent in a linear fashion on ethanol concentration. 5 Longer chain length alcohols up to n ‐decanol also bring about a negative going change in ΔΔV, and the dependence of ΔΔV on anaesthetic activity, with respect to increasing chain length of anaesthetic, is consistent with Traube's law. 6 Pentobarbitone added to the aqueous phase bathing the monolayer also elicits a negative ΔΔV, a finding which rules out the possibility of adsorption of the volatile alcohols to the measuring electrode. 7 The findings are discussed in terms of the proposition that increasing disorder in an array of fixed dipoles, such as might occur in a bilayer exposed to anaesthetic, would result in a lowering of the electrostatic barrier to the predominantly impermeable cation.