Potassium-Stimulated Respiration of Rat Cerebral Cortex: Effect of Ethanol on Tissue from Alcohol-Preferring and Nonpreferring Animals

Publisher Website
Google Scholar
Abstract
To determine whether the degree of central nervous system cellular adaptation was different in rats that showed preferential ingestion of ethanol under free-choice conditions and those that did not, the effects of ethanol on in vitro k-stimulated respiration of brain cortex was determined in 28 male hooded rats. Five groups of rats were studied: water controls; whisky-preferrers; ethanol-preferrers; whisky-nonpreferrers; and ethanol-nonpreferrers. Preferrers were those whose ratio of whisky (in 5 to 15% alcohol concentrations) or of ethanol (in 5 to 25% concentrations) intake to mean daily total fluid consumed exceeded 0. 50 under home-cage free-choice conditions. The animals were withdrawn from alcohol 24 hours prior to sacrifice by decapitation. Three brain slices from each hemisphere were obtained and placed in a Warburg vessel containing 3.0 ml volume of incubation medium. For k stimulation 100 mM KC1 was added. After equilibration, 0.2 ml of ethanol (750 mM concentration) was tipped in and readings taken at 15-minute intervals for 60 minutes. Respiration was determined from the cerebral cortex of each rat with and without added ethanol. A significant degree of suppression of k-stimulated respiration occurred in all groups when ethanol was added, suggesting that central nervous system cellular adaptation did not occur in any group of animals and that this biochemical assessment did not differentiate whisky-or ethanol-preferrers from nonpreferrers. These data are consistent with behavioral observations reported previously and indicate that preferential consumption of alcohol by rats cannot be equated with physiological addiction.