Solubility of volatile anesthetics in bovine white matter, cortical gray matter, thalamus, hippocampus, and hypothalamic area

Although known for whole brain, values are lacking for solubilities of modern volatile anesthetics in specific brain regions. Some regions should differ from others (e.g., gray matter versus white matter) because they differ in lipid content and because potent inhaled anesthetics are lipophilic. In the present report, we examined this issue in bovine brain, finding that white matter/gas partition coefficients are 1.6 (desflurane) to 2.4 (halothane) times larger than gray matter/gas partition coefficients, with values for isoflurane and sevoflurane lying between these at 1.9. Values for thalamus/gas, hypothalamic area/gas, and hippocampal/gas partition coefficients lie between those for gray and white matter. These data may be useful in defining the parts of the brain involved with return to consciousness during recovery from anesthesia.