Brain (Na + + K +)-activated adenosine triphosphatase activity and neurotransmitter uptake in alcohol-dependent rats

Abstract

Brain adenosine triphosphatase (ATPase) activity was examined in rats receiving varying doses of alcohol by inhalation of ethanol vapor for 7 days. Increased (Na + + K +)-dependent ATPase activity was observed in the microsomes and, to a lesser extent, in the crude mitochondrial fraction. Gradient centrifugation of the crude mitochondrial preparation showed, however, that the increase in (Na + + K +)-ATPase activity was in the synaptosomes. Increased (Na + + K +)-dependent activity could be correlated with alcohol dose, while (Mg 2+)-dependent ATPase activity was not altered significantly by the alcohol inhalation treatment. The synaptosomal uptake of 4 putative neurotransmitters was also examined in brain homogenates from rats receiving the highest dose of ethanol through inhalation. Despite a 30–40% increase in (Na + + K +)-ATPase activity, transmitter uptake was not enhanced. Of the putative neurotransmitters studied, the transport of norepinephrine, 5-hydroxytryptamine and GABA did not change while the uptake of glutamate decreased by 16%.