title: Vascular angiotensin and the sympathetic nervous system: do they interact?
abstract: We tested the hypothesis that local vascular formation of angiotensin (ANG) II and the sympathetic nervous system potentiate each other. Isolated rat hindquarters were perfused with an artificial medium, and ANG I and II release was measured by high-performance liquid chromatography and radioimmunoassay. Electrical stimulation of the lumbar sympathetic chain (0.5, 2, and 8 Hz) did not affect vascular ANG release in Sprague-Dawley (SD) rats. Hypertensive, ren-2 transgenic (TG+) rat hindquarters released significantly more ANG I (110 +/- 19 vs. 65 +/- 21 fmol/30 min in SD rats) and ANG II (235 +/- 22 vs. 140 +/- 30 fmol/30 min); however, nerve stimulation did not alter ANG release in TG+ rats. Captopril inhibited vascular ANG II release by 90%, but neither captopril nor ANG II receptor blockade by losartan affected the pressor response to nerve stimulation in SD and TG+ rats. Isoproterenol failed to increase either vascular ANG release or pressor response to nerve stimulation in SD or spontaneously hypertensive rat hindquarters. Exogenous renin, which increased vascular ANG release approximately 100-fold, prolonged the pressor responses to nerve stimulation. We conclude that the vascular renin-ANG system does not interact with the sympathetic nervous system locally. However, high concentrations of ANG II, which can be induced by circulation-derived renin, may prolong the duration of sympathetic nerve-induced vasoconstriction.
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Germany.
authors.forename: K F
authors.initials: KF
authors.lastname: Hilgers
authors.forename: R
authors.initials: R
authors.lastname: Veelken
authors.forename: I
authors.initials: I
authors.lastname: Kreppner
authors.forename: D
authors.initials: D
authors.lastname: Ganten
authors.forename: F C
authors.initials: FC
authors.lastname: Luft
authors.forename: H
authors.initials: H
authors.lastname: Geiger
authors.forename: J F
authors.initials: JF
authors.lastname: Mann
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000378:metabolism*; D004558:Electric Stimulation; D006614:Hindlimb / Q000098:blood supply; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000494:pharmacology; D012084:Renin-Angiotensin System / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D000318:Adrenergic beta-Agonists; D000804:Angiotensin II; D012083:Renin