ramipril and lacidipine

In this study, the effects of lacidipine (LAC), ramipril (RAM), and valsartan (VAL) on biochemical and histopathologic changes in heart tissue were studied in rats with isoproterenol-induced (ISO-induced) myocardial infarction (MI). LAC, RAM, and VAL had been administered via oral gavage at 3, 3, and 30 mg/kg doses, respectively, once per day during a 30-day time period. On days 29 and 30, the drug treatment group and the control group (with the exception of the intact control group, in which no medications were given, and ISO was not administered) were administered 180 mg/kg ISO subcutaneously over an interval of 24 h. After this period, the hearts of the rats were removed and processed for biochemical and histopathologic studies. The antioxidant parameters superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were estimated. A diagnosis of MI was confirmed with antioxidant parameters and histopathologic findings. In MI control groups, histopathologic indicators were found to be statistically higher than those in drug groups; an increase in histopathologic indicators of MI correlates with significant decreases in SOD and CAT levels, and an increase in MDA level. Histopathologic grades of MI indicators were significantly higher in MI group that did not receive any cardioprotective medications in comparison with MI groups that received LAC, RAM, and VAL. Each of the three medications favorably modulated most of the biochemical and histopathologic parameters observed. No significant difference existed with regard to any of the estimated parameters in the rat groups that received medications without MI induction. In conclusion, results indicate that LAC, RAM, and VAL significantly reduced myocardial injury and emphasize the cardioprotective nature of these agents.

Topics: Administration, Oral; Animals; Cardiotonic Agents; Dihydropyridines; Dose-Response Relationship, Drug; Isoproterenol; Male; Myocardial Infarction; Ramipril; Rats; Rats, Sprague-Dawley; Tetrazoles; Valine; Valsartan

In this study, effects of Lacidipine (LAC), Ramipril (RAM) and Valsartan (VAL) on DNA damage and oxidative stress occurred in acute and chronic periods after isoproterenol (ISO)-induced myocardial infarct (MI) were investigated in rats. LAC, RAM and VAL had been administered by oral gavage at 3, 3 and 30 mg/kg doses, respectively, in acute and chronic periods following MI. In acute MI model, LAC, RAM and VAL had been administered once per day to rat groups during 30 days. On days 29 and 30, the rats of the acute MI control and drug treatment groups were administered 180 mg/kg ISO, subcutaneously at an interval of 24 h. In chronic MI model, LAC, RAM and VAL had been administered to rat groups during 30 days, and on the 1st and 2nd days, the rats of the chronic MI control and drug treatment groups were administered ISO, by the same way. After this period, routine biochemistry indicators of MI, alanin aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase-isoenzymes (CK-MB), troponin I (TnI) and nitric oxide (NO), oxidative stress indicator, has been measured in the serums obtained from rat's blood. Also, 7,8-Dihydro-8-oxo-guanine (8-OHGua), which is an indicator of DNA damage level, has been determined in whole blood. After MI diagnosis, the relationships among the 8-OHGua, NO and clinic MI indicators have been determined. Results have been evaluated by comparing with that of control group. In control groups, the clinic MI indicators have been found to be statistically higher than the drug groups. In parallel to this increase in MI indicators, there have been determined a significant decrease in NO levels and an increase in 8-OHGua level. There was no significant difference in the rat groups which received drugs without MI induction. We have observed that the level of 8-OHGua which increased after MI in both acute and chronic periods decreased by LAC, RAM and VAL when compared to acute and chronic MI control groups. In conclusion, it has been determined that oxidative stress has been increased after ISO induced MI model and this stress reduces NO and even damages DNA. LAC, RAM and VAL may decrease the severity of MI and prevent DNA damage by reducing oxidative stress.

Topics: Animals; Antihypertensive Agents; Biomarkers; Dihydropyridines; DNA Damage; Guanine; Isoproterenol; Myocardial Infarction; Nitric Oxide; Oxidative Stress; Ramipril; Rats; Tetrazoles; Valine; Valsartan

To investigate the relative roles of angiotensin II, bradykinin, and calcium-dependent pathways in the genesis of mesenteric vascular hypertrophy in experimental diabetes.. Streptozotocin-induced diabetic Sprague-Dawley rats were randomly allocated to these treatments for 24 weeks: no treatment; ramipril at a hypotensive dose; ramipril plus the bradykinin type 2 receptor blocker icatibant; icatibant alone; ramipril at a low dose; the angiotensin II type 1 receptor antagonist, valsartan; the dihydropyridine calcium antagonist, lacidipine; and the nondihydropyridine calcium antagonist mibefradil.. Systolic blood pressure was serially measured every 4 weeks by tail-cuff plethysmography. We assessed the vascular architecture in sections of mesenteric arteries obtained after in-vivo perfusion, which were stained with an antibody to alpha-smooth muscle actin.. Both blood pressure and the mesenteric arterial wall: lumen ratio were reduced by administration of ramipril, at the high dose, either alone or in combination with icatibant, and also by valsartan. Treatment either with the low dose of ramipril or with the calcium antagonists lacidipine and mibefradil was associated with a decrease in the wall : lumen ratio of the mesenteric arteries without influencing blood pressure.. These findings demonstrate that blockade both of angiotensin II-dependent and of calcium-dependent pathways attenuates mesenteric vascular hypertrophy in experimental diabetes. Furthermore, the antitrophic effects of these antihypertensive agents may be independent of their hypotensive effects.

Topics: Actins; Angiotensin-Converting Enzyme Inhibitors; Animals; Benzimidazoles; Blood Pressure; Calcium Channel Blockers; Calcium Channels; Diabetes Mellitus, Experimental; Dihydropyridines; Hypertrophy; Male; Mesenteric Arteries; Mibefradil; Muscle, Smooth, Vascular; Peptidyl-Dipeptidase A; Ramipril; Random Allocation; Rats; Rats, Sprague-Dawley; Tetrahydronaphthalenes

The aim of this study was to compare the effects of angiotensin converting enzyme (ACE) inhibition, angiotensin II (AII) AT1-receptor blockade, and dihydropyridine calcium antagonism on hypertrophy and on vascular albumin permeability in kidney, heart, and mesenteric artery in a model combining genetic hypertension and diabetes mellitus. Diabetes mellitus was induced by streptozotocin in 8-week-old spontaneously hypertensive rats. The animals were randomized to receive no treatment, the angiotensin converting enzyme inhibitor ramipril, the AII AT1-receptor blocker valsartan, or the dihydropyridine calcium antagonist lacidipine for 3 weeks. Vascular albumin permeability was measured as the tissue content of intravenously injected Evans blue dye (EB) in kidney, heart, and mesenteric artery and the tissue/plasma EB ratio was calculated. Systolic blood pressure was reduced by all three antihypertensive regimens. Glycemic control was similar in all diabetic groups. Kidney hypertrophy was not affected by any of the antihypertensive drugs. Hypertrophy of the mesenteric artery was enhanced by lacidipine but was not affected by ramipril or valsartan. Relative heart weight was also increased by lacidipine. Vascular albumin permeability, expressed as EB content in micrograms/gram dry weight or as tissue/plasma EB ratio, was higher in the kidneys of lacidipine-treated rats than in any other group of diabetic rats. There was a positive correlation between kidney weight/body weight and kidney/plasma EB ratio in the diabetic rats. These findings indicate that the dihydropyridine calcium antagonist lacidipine is associated with an unfavorable effect on vascular hypertrophy and on vascular albumin permeability in the kidneys in rats with hypertension and diabetes mellitus. Furthermore, there seems to be a coupling in the diabetic kidney between hypertrophy and increased vascular albumin permeability.

Topics: Analysis of Variance; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Glucose; Blood Pressure; Capillary Permeability; Cardiomegaly; Coloring Agents; Coronary Vessels; Diabetes Mellitus, Experimental; Dihydropyridines; Evans Blue; Hypertension; Hypertrophy; Kidney; Male; Mesenteric Arteries; Ramipril; Rats; Rats, Inbred SHR; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renin; Serum Albumin; Tetrazoles; Valine; Valsartan