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Effects of volatile anesthetics on cardiac calcium channels
Author(s) -
Nakao S.,
Hirata H.,
Kagawa Y.
Publication year - 1989
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1989.tb02917.x
Subject(s) - enflurane , halothane , nitrendipine , isoflurane , anesthetic , volatile anesthetic , medicine , anesthesia , calcium , dissociation constant , partial pressure , chromatography , stereochemistry , oxygen , chemistry , organic chemistry , receptor
In order to investigate how volatile anesthetics affect cardiac calcium channels, the effects of halothane, enflurane, and isoflurane on the specific binding of [ 3 H]‐nitrendipine to bovine heart sarcolemmal membranes were studied. All three anesthetics added in liquid form inhibited [ 3 H]‐nitrendipine binding in a dose‐dependent manner, and more interestingly, the order of inhibition by these volatile anesthetics roughly followed that of their anesthetic potencies. The partial pressures, calculated using the gas/water partition coefficients of halothane, enflurane, and isoflurane which inhibited [ 3 H]‐nitrendipine binding by 30%, at 37°C were about 1.48 times 10 ‐2 atm. (1.48%), 4.89 times 10 ‐2 atm. (4.89%) and 2.76 times 10 ‐2 atm. (2.76%), resupectively. One mmol/l halothane altered not only the maximal binding (B max ) from 189 f mol/mg protein to 136 f mol/mg protein, but also the dissociation constant (Kd) from 0.074 nmol/l to 0.18 nmol/l. Halothanc was also added to the reaction mixture in the gaseous form with air. The partial pressure of halothane needed to bring about 30% inhibition was 0.82 times 10 ‐2 (0.82%), a value almost similar to that for halothane added in the liquid form. These results indicate that all three volatile anesthetics have direct effects on cardiac calcium channels, and that the magnitude of the effects depends on their anesthetic potencies.