Tissue specificity of dopamine effects on brain ATPases.

Dopamine inhibits Mg2+,Na+,K+- and Na+,K+-ATPase activities but does not modify Mg2+-ATPase activity of nerve ending membranes isolated from rat cerebral cortex. In the presence of the soluble fraction of brain, dopamine activates total, Na+,K+-, and Mg2+-ATPases. Dopamine stimulation of nerve ending membrane ATPases is achieved when soluble fractions of brain, kidney, or liver are used. On the other hand, dopamine effects are not observed on kidney or heart ATPase preparations. The results indicate tissue specificity of dopamine effect with respect to the enzyme source; there is no tissue specificity for the requirement of the soluble fraction to achieve stimulation of ATPases by dopamine.