Angiotensin II-noradrenergic interactions in renovascular hypertensive rats.
This study tested the hypothesis that interactions of endogenous angiotensin II (AII) with the noradrenergic neuroeffector junction are important in renin-dependent hypertension. In the in situ blood-perfused rat mesentery, in normal rats exogenous AII potentiated mesenteric vascular responses to periarterial (sympathetic) nerve stimulation (PNS) more than vascular responses to exogenous norepinephrine (NE). In 2-kidney-1-clip (2K-1C) rats with renovascular hypertension mesenteric vascular responses to PNS and NE were greater than in sham-operated rats, and renovascular hypertension mimicked the effects of exogenous AII with respect to enhancing responses to PNS more than responses to NE. In 2K-1C rats, but not in sham-operated rats, 1-Sar-8-Ile-AII markedly suppressed vascular responses to PNS, without influencing responses to NE. Finally, 1-Sar-8-Ile-AII attenuated sympathetic nerve stimulation-induced neuronal spillover of NE in 2K-1C rats, but not in sham-operated rats. These data indicate that renovascular hypertension enhances noradrenergic neurotransmission, and that this enhancement is mediated in part by AII-induced facilitation of NE release.
Zimmerman
J B
JB
Robertson
D
D
Jackson
E K
EK
D000803:Angiotensin I / Q000097:blood; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure; D002908:Chronic Disease; D004558:Electric Stimulation; D006978:Hypertension, Renovascular / Q000503:physiopathology*; D009638:Norepinephrine / Q000502:physiology*; D051381:Rats; D012077:Renal Artery / Q000502:physiology; D012083:Renin / Q000097:blood; D013564:Sympathetic Nervous System / Q000502:physiology; D014655:Vascular Resistance
D000804:Angiotensin II; D000803:Angiotensin I; D012083:Renin; D009638:Norepinephrine