title: Renal sympathetic nerve activity and the exaggerated natriuresis of the spontaneous hypertensive rat.
abstract: To evaluate the role of altered efferent renal sympathetic nerve activity in the exaggerated natriuresis of the spontaneous hypertensive rat (SHR), we measured efferent renal sympathetic nerve activity in anesthetized age- and sex-matched SHR and normotensive Wistar Kyoto (WKY) control rats during control and intravenous saline volume expansion. Mean arterial pressure was 40-60 mm Hg higher in SHR than in WKY. During volume expansion, the increment in urinary flow rate (17.5 +/- 3.1 vs 42.8 +/- 8.0 microliters/100 g/min) and sodium excretion (8.1 +/- 1.5 vs 15.2 +/- 2.3 muEq/min) were greater in SHR than in WKY. During control, efferent renal sympathetic nerve activity was 12.2 +/- 0.4 Hz in WKY and 12.0 +/- 0.5 Hz in SHR and fell equally during volume expansion to 5.0 +/- 0.6 Hz in WKY and to 4.0 +/- 0.8 Hz in SHR. Thus, these studies demonstrate that the exaggerated natriuresis of SHR as compared to WKY cannot be attributed to differences in reflex withdrawal of renal sympathetic nerve activity.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D007668:Kidney / Q000294:innervation*; D008297:Male; D009318:Natriuresis; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D013564:Sympathetic Nervous System / Q000503:physiopathology*
chemical_list: D009638:Norepinephrine