Drugs online research references
Br J Pharmacol. 1997 Dec;122(7):1385-94.
Investigation of the inhibitory effect of N(G)-nitro-L-arginine methyl ester on the antihypertensive effect of the angiotensin AT1 receptor antagonist, GR138950.
Anderson IK, Drew GM.
Disease Sciences, Glaxo Wellcome Medicines Research Centre, Stevenage, Hertfordshire.
1. The effect of systemic administration of the nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME) on the antihypertensive effects of the angiotensin AT1 receptor antagonist, GR138950, the angiotensin-converting enzyme (ACE) inhibitor, enalapril, or hydralazine has been evaluated in unrestrained, conscious renal artery ligated hypertensive (RALH) rats. The effect of the phosphodiesterase type V inhibitor, zaprinast on the antihypertensive effect of GR138950 in RALH rats was also examined. The effect of GR138950 on blood pressure, and plasma and urine cyclic GMP levels was compared to that of zaprinast in conscious RALH rats. 2. GR138950, enalapril or hydralazine caused marked reductions in blood pressure associated with immediate tachycardia in conscious RALH rats. L-NAME pretreatment attenuated the antihypertensive effects of GR138950 or enalapril but not that of hydralazine in conscious RALH rats. The initial tachycardia caused by GR138950 or enalapril but not hydralazine was attenuated by L-NAME pretreatment. L-NAME alone caused a transient (20 min) pressor response and a prolonged (6 h) bradycardia in conscious RALH rats. 3. Pretreatment with indomethacin did not affect the cardiovascular effect of GR138950 in conscious RALH rats. Indomethacin alone did not significantly change basal blood pressure or heart rate in RALH rats. 4. Zaprinast pretreatment did not affect the antihypertensive effect of GR138950 in conscious RALH rats but potentiated the depressor response to sodium nitroprusside. Zaprinast alone caused a small reduction in basal blood pressure but did not change basal heart rate in RALH rats. 5. The antihypertensive effect of GR138950 was not associated with an increase in plasma or urine cyclic GMP levels in conscious RALH rats, whereas zaprinast caused a small fall in blood pressure associated with increases in plasma and urine cyclic GMP. 6. The ability of L-NAME to inhibit the antihypertensive action of GR138950 or enalapril suggests that these agents release nitric oxide (NO) and/or enhance the cardiovascular effects of NO as part of their mechanism of action. However, the inability of zaprinast to potentiate the antihypertensive effects of GR138950 and the finding that GR138950 did not increase urine and plasma cyclic GMP levels are not consistent with this view. Attenuation of the response to GR138950 or enalapril, but not hydralazine, suggests a selective interaction between L-NAME and inhibitors of the renin-angiotensin system, although the nature of this interaction is unknown.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9421286&dopt=Abstract
Eur J Pharmacol. 1986 Mar 11;122(1):59-64.
Converting enzyme inhibitor-induced changes of plasma angiotensinogen concentration in the rat.
Radziwill R, Stuzmann M, Hilgenfeldt U, Hackenthal E.
Chronic treatment with converting enzyme inhibitors induces a fall of plasma angiotensinogen concentration, which is thought to result from increased consumption by renin. As this explanation cannot account for all the observations, we reexamined this effect. Rats received captopril (50 mg/kg per day), enalapril (10 mg/kg per day) or Hoe 498 (1 mg/kg per day) for 7 days. Plasma angiotensinogen (by indirect assay) fell to 34, 37 and 43% of its initial values, respectively. Total immunoreactive angiotensinogen (by direct radioimmunoassay, which also measures des-AI-angiotensinogen) was 76, 70 and 95% of the initial values, respectively. This suggests that a major part of the fall of intact angiotensinogen can be attributed to increased cleavage by renin, but an additional factor is likely to be involved. Experiments with isolated hepatocytes indicated that converting enzyme inhibitors in high concentrations may have a direct effect on angiotensinogen secretion. Whether this can account for the fall in total immunoreactive angiotensinogen in vivo remain unclear.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3007179&dopt=Abstract
Eur J Pharmacol. 1985 Apr 16;110(3):323-8.
Potentiation of the inhibitory effect of a thromboxane A2 antagonist (L-640,035) on arterial thrombosis formation in rabbit by the angiotensin converting enzyme inhibitor enalapril.
Chan CC, Ford-Hutchinson A.
The angiotensin converting enzyme inhibitor enalapril (0.5 mg/kg i.v.) potentiated significantly the inhibitory effect of the thromboxane A2 antagonist L-640,035 (1 mg/kg i.v.) on electrically induced platelet accumulation in the rabbit in vivo. Enalapril had no effect upon platelet accumulation when given alone. The hypotensive effects of enalapril did not account for the potentiation because a combination of hexamethonium (5 mg/kg i.v.) and hydralazine (1 mg/kg i.v.), which decreased blood pressure similarly to enalapril, did not augment the effect of L-640,035. Determination by radioimmunoassay of plasma levels of immunoreactive 6-keto-PGF1 alpha, suggested that increases in PGI2 levels after combined administration of enalapril and L-640,035 could explain the observed potentiation.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2988983&dopt=Abstract
online pharmacies ||
Hair Million herbal formula for hair loss and hair growth ||
Amoxicillin ||
Tramadol ||
Paxil ||
Rx Drugs USA, Prescription Drugs Online Pharmacy ||
Zithromax ||
online pharmacy ||
Antibiotics and prescription medications online literature ||
Antibiotics