Effects of norepinephrine on 86Rb-uptake by arteries from spontaneously hypertensive and Wistar-Kyoto rats.

The effects of norepinephrine on Na+ -pump activity and cell Na+ were determined using carotid and tail arteries from Wister-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Maximum and control Na+ -pump activities were elevated in SHR versus WKY arteries. Cell Na+ was only elevated in Na+ -loaded SHR tail arteries. Norepinephrine increased control Na+ -pump activity in both SHR and WKY, and also increased control cell Na+ levels, but only in carotid arteries, of both groups. The increased control Na+ -pump activity produced by norepinephrine may be secondary to increased cell Na+ in carotid arteries, but not in tail arteries. The elevated Na+ -pump activity in SHR arteries does not appear to be caused by elevated cell Na+.