Regional differences in brain norepinephrine and dopamine uptake kinetics in inbred rat strains with hypertension and/or hyperactivity.

High-affinity uptake of norepinephrine (NE) and dopamine (DA) were determined in synaptosomes of brain regions from four genetically related inbred rat strains, all derived from the Wistar-Kyoto rat: SHR, WKY, WKHA and WKHT strains. SHRs express hypertension and hyperactivity, WKHAs express hyperactivity alone, WKHTs express hypertension alone, and WKYs are neither hypertensive nor hyperactive. Significant increases in NE uptake, primarily in Vmax, in cerebral cortical areas and the cerebellum, were associated with the hypertensive trait. Significant increases in DA uptake Vmax in the frontal cortex were associated with the inheritance of hyperactivity among these strains. A limited study in SHRs indicated that DA uptake in the frontal cortex increased with age, and that males did not differ from females. No changes in DA uptake in the neostriatum were found with respect to either strain, or age or sex. These findings revealed changes in brain catecholamine neuronal function that are of relevance to both hypertension and hyperactivity. This was made possible by the availability of WKHA and WKHT, in addition to WKYs, as appropriate controls for the SHR.