Drugs online research references
J Cardiovasc Pharmacol. 1986 May-Jun;8(3):449-58.
Electropharmacological effects of a new dihydropyridine analog on isolated guinea pig papillary muscles and Purkinje fibers.
Molyvdas PA, Sperelakis N.
The effects of a new dihydropyridine, FR-34235, were compared with those of the dihydropyridine, nifedipine, and verapamil on the normal fast action potentials (APs), slow APs, and contractions of guinea pig papillary muscles and Purkinje fibers. FR-34235 (10(-6) M) blocked the contractions of papillary muscles superfused with normal Tyrode solution within 10-12 min. Maximal upstroke velocity (+Vmax) and overshoot of the fast APs were not affected, whereas the AP durations at 50 and 90% repolarization (APD50 and APD90) were shortened. The effects of FR-34235 on the fast APs and contractions were reversed within 10 min on washout. To determine the effects of the calcium antagonists on slow APs, the fast Na+ channels were inactivated by partial depolarization (to approximately -45 mV) by elevated [K]0, and isoproterenol (10(-6) M) or histamine (10(-5) M) was used to induce slow APs on stimulation. Nifedipine (10(-7) M) and verapamil (2 X 10(-6) M) completely blocked the slow APs. FR-34235 depressed (3 X 10(-8) M) and blocked (10(-7) M) the slow APs in a frequency-dependent manner. The effects were reversed by elevated [Ca]0 or washout of the drug. The contractions accompanying the slow APs were depressed and blocked in parallel with the depression of +Vmax. In guinea pig Purkinje fibers, FR-34235 had no significant effect on the fast AP parameters but produced a marked depression of automaticity. FR-34235 also blocked the slow APs of the Purkinje fibers in a frequency-dependent manner; all drug effects were reversed within 10 min on washout.(ABSTRACT TRUNCATED AT 250 WORDS)
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2425157&dopt=Abstract
J Cardiovasc Pharmacol. 1987 Oct;10(4):456-61.
Comparison between the effects of MDL 72567 and nifedipine on various cardiovascular parameters in conscious sinoaortic-denervated rats and sham-operated controls.
Petty MA, Spedding M, Di Francesco GF.
Merrell Dow Research Institute, Strasbourg Research Center, France.
In this study the effects of a new calcium entry blocking agent, 2,6-dimethyl-3-methoxycarbonyl-4-(2-nitrophenyl)-5-(2-furoyl)-1, 4-dihydropyridine (MDL 72567), were compared with those of nifedipine on blood pressure, heart rate, ECG, and cardiac contractility indices in conscious sinoaortic baroreceptor-denervated (SA-denervated) rats and their sham-operated controls. In sham-operated rats, the calcium-entry blocking agents (0.1-2 mg/kg i.v.) produced equivalent falls in blood pressure. However, nifedipine caused a much greater reflex tachycardia which was accompanied by a negative inotropic effect, and with the highest dose (2 mg/kg), a prolongation of the PQ interval. MDL 72567 induced an increase in myocardial contractility. In SA-denervated rats, both drugs produced an enhanced fall in blood pressure accompanied by a negative inotropic effect. Nifedipine did not change heart rate in SA-denervated rats, whereas MDL 72567 caused bradycardia. Thus, in these experiments, MDL 72567 caused less reflex tachycardia for a given fall in blood pressure than nifedipine and was less likely to cause myocardial depression. These effects of MDL 72567 may represent valuable, clinically relevant advantages over nifedipine.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2444800&dopt=Abstract
J Cardiovasc Pharmacol. 1987;10 Suppl 10:S147-8.
Acute antihypertensive effect of nifedipine on high and low salt diet.
Luque-Otero M, Fernandez-Pinilla C, Catalan P, Martell-Claros N, Fernandez-Cruz A, Martinez-Gomez ME.
Hypertension Unit, Hospital Clinico San Carolos, Complutense University, Madrid, Spain.
To examine the influence of sodium balance in the acute response to nifedipine, we studied 10 untreated essential hypertensive patients aged 29 to 43 years. Blood pressure was recorded with the patients fasting and lying in the supine position, and 10 mg nifedipine was administered sublingually. Blood pressure was recorded again 3 h after nifedipine. Patients were studied after 1 week on both their unrestricted usual diet (NaU 206 +/- 29 mmol/day) and a low salt diet (NaU 66 +/- 8 mmol/day). The maximum hypotensive effect of nifedipine was observed at 90 min. The decrease of blood pressure tended to be greater and longer on high salt than low salt diet. Our results suggest that the acute antihypertensive effect of nifedipine is enhanced by sodium administration.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2455119&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 ||