OBJECTIVE To assess the importance, for vasoconstriction, of in situ angiotensin (Ang) II generation, as opposed to ang II delivery to AT receptors via the organ bath fluid. METHODS Ang I and II concentration-response curves in human and porcine coronary arteries (HCAs, PCAs) were constructed in relation to estimates of the clearances of Ang I and II (ClAngI, ClAngII) from the organ bath and ...

We investigated the angiotensin II (Ang II)-generating system by analyzing the vasoconstrictor effect of Ang II, angiotensin J (Ang I), and tetradecapeptide (TDP) renin substrate in the absence and presence of inhibitors of the renin-angiotensin system in isolated rat aortic rings and mesenteric arterial beds with and without functional endothelium. Ang II, Ang I, and TDP elicited a dose-depend...

We studied the role of aldosterone (aldo) in myocardial injury in a model of angiotensin (Ang) II-hypertension. Wistar rats were given 1% NaCl (salt) to drink and randomized into one of the following groups (n = 10; treatment, 21 d): 1) vehicle control (VEH); 2) Ang II infusion (25 ng/min, sc); 3) Ang II infusion plus the selective aldo blocker, eplerenone (epl, 100 mg/kg.d, orally); 4) Ang II ...

Using type 1a angiotensin receptor (AT1a) receptor-deficient (Agtr1a-/-) mice and in vivo autoradiography, we tested the hypothesis that intracellular uptake of ANG II in the kidney and adrenal glands is primarily mediated by AT1a receptors and that the response is regulated by prevailing endogenous ANG II. After pretreatment of wild-type (Agtr1a+/+) and Agtr1a-/- mice (n = 6-9 each group) with...

Intracellular ANG II induces biological effects in nonrenal cells, but it is not known whether it plays a physiological role in renal proximal tubule cells (PTCs). PTCs express angiotensinogen, renin, and angiotensin-converting enzyme mRNAs, suggesting the presence of high levels of intracellular ANG II. We determined if microinjection of ANG II directly in single PTCs increases intracellular c...

Angiotensin (Ang) II regulates adrenal steroidogenesis and adrenal cortical arterial tone. Vascular metabolism could decrease Ang II concentrations and produce metabolites with vascular activity. Our goals were to study adrenal artery Ang II metabolism and to characterize metabolite vascular activity. Bovine adrenal cortical arteries were incubated with Ang II (100 nmol/L) for 10 and 30 minutes...

Hypertension induced by long-term infusion of angiotensin II (Ang II) is associated with augmented intrarenal Ang II levels to a greater extent than can be explained on the basis of the circulating Ang II levels. Although part of this augmentation is due to AT(1) receptor-dependent internalization, the intracellular compartments involved in this Ang II accumulation remain unknown. In the presen...

Hypertension induced by long-term infusion of angiotensin II (Ang II) is associated with augmented intrarenal Ang II levels to a greater extent than can be explained on the basis of the circulating Ang II levels. Although part of this augmentation is due to AT1 receptor–dependent internalization, the intracellular compartments involved in this Ang II accumulation remain unknown. In the present ...

OBJECTIVE Angiotensin II (Ang II), the main product of renin-angiotensin system (RAS) has a well-known role in cardiovascular regulation. Over-production of Ang II is one of the important underlying mechanisms of hypertension. In this study, the effect of crocin on cardiovascular responses in rats with acute hypertension induced by Ang II was evaluated. MATERIALS AND METHODS Rats were divided...

The objective of this study was to determine the contribution of renal nerves to the enhanced afferent arteriolar reactivity observed in angiotensin II (Ang II)-induced hypertension. Uninephrectomized Sprague-Dawley rats were divided into four groups: sham rats, renal-denervated rats, Ang II-infused (at 40 ng/min for 13 days) rats, and Ang II-infused+renal-denervated rats. With the use of an im...