The influence of tissue treatment on brain Na+, K+-ATPase activity and its response to vanadate inhibition.

This study has compared the effect of freezing in situ and decapitation without freezing on the Na+,K+-ATPase activity in mouse cerebral cortex homogenates under otherwise comparable conditions. The Na+,K+-ATPase activity was substantially influenced by the sample preparation; a twofold value was obtained for frozen samples as compared to that in fresh samples. Not only basal activity, but also the sensitivity of the enzyme towards vanadate inhibition depended on tissue treatment; lesser inhibition was observed in frozen samples. These findings suggest the possible implication of altered enzyme characteristics due to sample preparation while studying the influence of various other factors on enzyme activity.