The Shaker Potassium Channel Is No Target for Xenon Anesthesia in Short-SleepingDrosophila melanogasterMutants

Abstract

Background. Xenon seems to be an ideal anesthetic drug. To explore if next to the antagonism at the NMDA-receptor other molecular targets are involved, we tested the xenon requirement in short sleepingDrosophilashaker mutants and in .Methods. TheDrosophila melanogasterstrains wildtype Canton-S, , and , were raised and sleep was measured. Based on the response of the flies at different xenon concentrations, logEC50 values were calculated.Results. The logEC50-values for WT Canton-S were 1.671 (1.601–1.742 95%-confidence intervall; ;Pversus > 0,05), for 1.711 (1.650–1.773; ;Pversus WT Canton-S > 0,05). The logEC50-value for was 1.594 (1.493–1.694; ;Pversus > 0.05). The logEC-value of was 2.076 (1.619–2.532; ;Pversus < 0.05, versus < 0.05, versus WT Canton-S < 0.05).Pvalues for all shaker mutants were , while was found to be hyposensitive compared to wildtype (P< 0.05).Conclusions. The xenon requirement inDrosophila melanogasteris not influenced by a single gene mutation at the shaker locus, whereas a reduced expression of a nonselective cation channel leads to an increased xenon requirement. This supports the thesis that xenon mediates its effects not only via an antagonism at the NMDA-receptor.