Effects of hypercholesterolemia on the contractions to angiotensin II in the isolated aorta and iliac artery of the rabbit: role of arachidonic acid metabolites. Volume-overload cardiac hypertrophy is unaffected by ACE inhibitor treatment in dogs. Ramipril prevents hypersensitivity to phenylephrine in aorta from streptozotocin-induced diabetic rats. Rx drugs

online pharmacy, prescription drugs online

Drugs online research references

J Cardiovasc Pharmacol. 1997 Jul;30(1):118-23.
Effects of hypercholesterolemia on the contractions to angiotensin II in the isolated aorta and iliac artery of the rabbit: role of arachidonic acid metabolites.

Dam JP, Vleeming W, Riezebos J, Post MJ, Porsius AJ, Wemer J.

Utrecht University, Faculty of Pharmacy, Department of Pharmacoepidemiology & Pharmacotherapy, The Netherlands.

The aim of this study was to investigate the effect of hypercholesterolemia on the angiotensin II-induced contractions in the isolated aorta and iliac artery of the rabbit, with respect to the role of arachidonate metabolites. Furthermore, the effect of the angiotensin-converting enzyme inhibitor ramipril was studied on the responses to angiotensin II in the cholesterol-fed rabbit. After 12 weeks of cholesterol diet (0.3%), endothelium-dependent relaxations to acetylcholine were significantly fewer compared with control (30.2 +/- 5.9% vs. 73.0 +/- 1.7%) in the aorta but not in the iliac artery of the rabbit. The angiotensin II- and methoxamine-induced contractions were also significantly lower compared with control in the aorta (101.4 +/- 6.7% vs. 60.9 +/- 4.2% and 160.2 +/- 5.7% vs. 135.8 +/- 8.0%, respectively) but not in the iliac artery. The lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) selectively attenuated the angiotensin II-induced contractions in rabbit aortic rings from the control group only in the presence of the endothelium, whereas it had no effect on the responses to angiotensin II in the cholesterol group (with or without endothelium). In the iliac artery, NDGA inhibited the responses to angiotensin II in both the control and cholesterol groups. Treatment with ramipril (0.33 mg/kg/day) significantly improved the maximal angiotensin II-induced contraction in the aorta of rabbits fed a cholesterol diet for 16 weeks to 61.0 +/- 7.3% (vs. 32.7 +/- 9.0% in the cholesterol group). We conclude that hypercholesterolemia leads to a reduction of angiotensin II-induced contractions in the aorta and not in the iliac artery of the rabbit. This reduction might be related to loss of endothelium-dependent lipoxygenase products and is partially reversed by ramipril.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9268230&dopt=Abstract

Am J Physiol. 1997 Aug;273(2 Pt 2):H961-70.
Volume-overload cardiac hypertrophy is unaffected by ACE inhibitor treatment in dogs.

Dell'italia LJ, Balcells E, Meng QC, Su X, Schultz D, Bishop SP, Machida N, Straeter-Knowlen IM, Hankes GH, Dillon R, Cartee RE, Oparil S.

Department of Medicine, Birmingham Veterans Affairs Medical Center, Alabama, USA.

We tested the hypothesis that angiotensin-converting enzyme (ACE) inhibitor therapy prevents volume-overload hypertrophy in dogs with chronic mitral regurgitation (MR). Seven adult mongrel dogs receiving ramipril (R; 10 mg orally, twice/day) for 4 mo were compared with 11 dogs receiving no R (N) for 4 mo after induction of MR. Cine-magnetic resonance imaging demonstrated that left ventricular (LV) mass increased in the R-MR dogs [80 +/- 4 (SE) to 108 +/- 7 g, P < 0.01] and in the N-MR dogs (92 +/- 7 to 112 +/- 8 g, P < 0.001). LV myocyte cell length was greater in the R-MR and N-MR dogs (203 +/- 6 and 177 +/- 10 microns, respectively) than in normal (144 +/- 4 microns, P < 0.05) dogs. There was significant loss of the collagen weave pattern by scanning electron microscopy in both R-MR and N-MR dogs. LV ACE and chymase activities were significantly elevated in R-MR and N-MR compared with normal dogs. LV angiotensin II (ANG II) levels in the R-MR dogs (28 +/- 12 pg/g) were reduced to levels seen in normal dogs (28 +/- 4 pg/g) compared with N-MR dogs (72 +/- 11 pg/g, P < 0.05). Steady-state AT1-receptor mRNA levels decreased 66% in N-MR compared with normal dogs (P < 0.001) and increased 1.5-fold in R-MR compared with normal dogs (P < 0.01). Thus upregulation of the AT1 receptor in the R-MR hearts may provide a mechanism by which normal intracardiac ANG II levels could continue to mediate LV hypertrophy. However, the mechanism of dissolution collagen weave in both N-MR and R-MR hearts may be related to the stretch of volume overload.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9277516&dopt=Abstract

Diabetologia. 1994 Jul;37(7):664-70.
Ramipril prevents hypersensitivity to phenylephrine in aorta from streptozotocin-induced diabetic rats.

Murray P, Pitt B, Webb RC.

Department of Physiology, University of Michigan, Ann Arbor.

This study investigated the protective effect of the angiotensin converting enzyme inhibitor, ramipril, on endothelium-dependent responses in arteries from control (CON) and streptozotocin-induced (STZ) diabetic rats. Three hypotheses were tested: 1) there is an endothelium-dependent component to the increased alpha-adrenergic responsiveness characteristic of diabetes; 2) endothelium-dependent, acetylcholine-induced relaxation is attenuated in aorta from diabetic rats; and 3) ramipril (3 mg/kg daily in the food, 12-15 weeks) will prevent functional vascular changes in diabetic rats. Vascular function was assessed in aortic rings using standard muscle bath procedures for measurement of isometric force. Sensitivity to phenylephrine was increased in aortic rings from diabetic compared to control values [pD2 values (-log ED50): CON = 6.22 +/- 0.12, STZ = 7.54 +/- 0.11), and removal of the endothelium (-Endo) increased phenylephrine sensitivity (CON-Endo = 7.40 +/- 0.11, STZ-Endo = 8.32 +/- 0.18). The magnitude of the shift in responsiveness following endothelium removal was greatest in control rats. Ramipril treatment (Ram) partially normalized phenylephrine responsiveness in intact (STZ + Ram = 6.55 +/- 0.11) and denuded (STZ-Endo + Ram = 7.75 +/- 0.10) vessels. Vasodilatation to acetylcholine and nitroglycerin was not altered in diabetic rats nor was it affected by ramipril treatment. Diabetes increases contractile sensitivity to phenylephrine but not to vasodilators and chronic ramipril treatment prevents this increase in contractile sensitivity. Ramipril treatment did not alter the hyperglycaemic condition induced by streptozotocin. The changes in phenylephrine sensitivity appear to involve an endothelial and a smooth muscle component.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7958536&dopt=Abstract

Herbs and Pharmaceuticals Online || Hair Million herbal formula for hair loss and hair growth || Wellstreet online pharmacy for click-order prescription medications || Altace Online Pharmacy || Rx Drugs USA, Prescription Drugs Online Pharmacy || Insurance plans and information || Insurance policies for all purposes || Antibiotics and prescription medications online literature ||