title: Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats.
abstract: This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo.
authors.affiliation: Department of Cardiology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Chelko
authors.affiliation: Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA.
authors.forename: Chad W
authors.initials: CW
authors.lastname: Schmiedt
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA.
authors.forename: Tristan H
authors.initials: TH
authors.lastname: Lewis
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA.
authors.forename: Tom P
authors.initials: TP
authors.lastname: Robertson
authors.affiliation: Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4984, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Lewis