Anesthesia cutoff phenomenon: interfacial hydrogen bonding.
Anesthesia "cutoff" refers to the phenomenon of loss of anesthetic potency in a homologous series of alkanes and their derivatives when their sizes become too large. In this study, hydrogen bonding of 1-alkanol series (ethanol to eicosanol) to dipalmitoyl-L-alpha-phosphatidylcholine (DPPC) was studied by Fourier transform infrared spectroscopy (FTIR) in DPPC-D2O-in-CCl4 reversed micelles. The alkanols formed hydrogen bonds with the phosphate moiety of DPPC and released the DPPC-bound deuterated water, evidenced by increases in the bound O-H stretching signal of the alkanol-DPPC complex and also in the free O-D stretching band of unbound D2O. These effects increased according to the elongation of the carbon chain of 1-alkanols from ethanol (C2) to 1-decanol (C10), but suddenly almost disappeared at 1-tetradecanol (C14). Anesthetic potencies of these alkanols, estimated by the activity of brine shrimps, were linearly related to hydrogen bond-breaking activities below C10 and agreed with the FTIR data in the cutoff at C10.
Chiou
J S
JS
Department of Anesthesia, University of Utah School of Medicine, Salt Lake City.
Ma
S M
SM
Kamaya
H
H
Ueda
I
I
D015060:1,2-Dipalmitoylphosphatidylcholine; D000438:Alcohols; D000758:Anesthesia; D002251:Carbon Tetrachloride; D003903:Deuterium; D017666:Deuterium Oxide; D005583:Fourier Analysis; D006860:Hydrogen Bonding; D008081:Liposomes; D008954:Models, Biological; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014867:Water
D000438:Alcohols; D008081:Liposomes; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; D003903:Deuterium; D002251:Carbon Tetrachloride; D017666:Deuterium Oxide