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EFFECTS OF HALOTHANE ON THE INCORPORATION OF [ 14 C]‐SERINE INTO PHOSPHOLIPID IN THE GUINEA‐PIG ILEUM
Author(s) -
PATON W.D.M.,
WING D.R.
Publication year - 1981
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.1476-5381.1981.tb10989.x
Subject(s) - halothane , phosphatidylserine , phospholipid , phosphatidylethanolamine , chemistry , serine , guinea pig , threonine , biochemistry , ileum , chromatography , biophysics , membrane , phosphatidylcholine , biology , endocrinology , enzyme , organic chemistry
1 The effects of halothane on the incorporation of l ‐[3‐ 14 C]‐serine into phospholipid were studied in the resting, innervated longitudinal muscle preparation of the guinea‐pig ileum. 2 The anaesthetic, at clinical concentrations, caused a dose‐dependent, partial inhibition of incorporation. The effect was rapid and reversible, and did not show characteristics of competitive inhibition. 3 The incorporation was reduced by a decrease in the Ca 2+ concentration of the Krebs incubation buffer. Part of the activity persisted in the absence of added Ca 2+ and this was most susceptible to inhibition by halothane. Sensitivity to external Ca 2+ was not influenced at the halothane concentrations studied. 4 Evidence in support of the 14 C‐incorporation being due to l ‐[3‐ 14 C]‐serine‐phospholipid base‐exchange activity included: (a) the rapid appearance of radioactivity in phosphatidylserine; (b) the kinetics of this incorporation in relation to that in phosphatidylethanolamine; (c) its dependence on Ca 2+ , and (d) its insensitivity to 2,4‐dinitrophenol and its sensitivity to temperature. 5 It is concluded that this preparation makes it possible for a membrane‐bound lipid‐dependent activity ( l ‐serine‐phospholipid base‐exchange) to be studied in conditions of cellular integrity under which the normal functional effects of lipophilic drugs can be simultaneously tested. 6 A rapid gas‐chromatographic assay for halothane from an aqueous medium is also described.