Drugs online research references
Can J Physiol Pharmacol. 1990 Dec;68(12):1542-7.
Deuterium oxide reduces agonist and depolarization-induced contraction of rat aortic rings.
McWilliam TM, Liepins A, Rankin AJ.
Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada.
The influence of deuterium oxide (D2O) on calcium-dependent vascular smooth muscle contraction was investigated. The effect of D2O on receptor-operated calcium channels was investigated with phenylephrine-induced contraction in the rat aortic ring preparation. D2O depressed the contraction response in a dose-dependent manner with 50% inhibition of maximum contraction observed with 60% D2O. The effect of 60% D2O on phenylephrine-induced contraction was reversible and not dependent on an intact endothelium. Sixty percent D2O also reduced potassium chloride induced contractions by 50%, indicating an effect on voltage-operated calcium channels. Studies with Bay K 8644, and L-type calcium channel activator, confirm an effect on utilization of extracellular calcium sources and on the voltage-operated calcium channel. Sixty percent D2O also depressed a calcium contraction dose-response curve by approximately 25%. Likewise, a change in the pD2' for nifedipine in the presence of D2O may indicate an effect on the nifedipine binding site and (or) the voltage-dependent calcium channel. Further studies were performed to determine whether the D2O effects were nonspecific or selective effects on the receptor- and voltage-operated calcium channels. Sucrose-induced contaction in the presence of 60% D2O was found to be inhibited by approximately 50%. D2O similarly affected isoprenaline relaxation, which would suggest a nonspecific D2O effect on the vascular smooth muscle contractile process.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1707743&dopt=Abstract
Prostaglandins Leukot Essent Fatty Acids. 1989 Feb;35(2):113-8.
Factors subserving the enhancing effect of progesterone on the output of prostaglandin F2 alpha in uteri from ovariectomized rats.
Franchi AM, Gimeno MA, Gimeno AL.
Centro de Estudios Farmacologicos y de Principios Naturales, Buenos Aires, Argentina.
The effects of progesterone (P4) and of calcium-ionophore A-23187, on the release of prostaglandins (PGs) E2 and F2 alpha, in uteri isolated from ovariectomized rats and the influences of mepacrine and nifedipine, were explored. The metabolism of labelled arachidonic acid (AA) into different prostanoids (6-keto-PGF 1 alpha, PGE 2 and PGF2 alpha) in uterine segments from spayed rats, injected or not with P4, was also studied. In all cases ovariectomy was performed 20-25 days prior to sacrifice. One group of spayed rats were injected with 4.0 mg of P4 during two days and sacrificed 24 h after the last injection. The remaining spayed animals were considered as controls. Tissue samples from both groups were incubated for one hour in the absence or in the presence of either A-23187 (1.0 microgram/ml), mepacrine (10(-3) M) or nifedipine (10(-6) M), or a combination of A-23187 plus mepacrine. At the end of the incubating period PGs in the suspending solution were extracted, separated, identified (TLC) and quantitated. The metabolism of 14C-AA into different prostanoids was explored in uterine segments from spayed rats, injected or not with P4 prior to sacrifice. Tissue prepared from P4-injected rats as well as those from rats not receiving P4 but incubated with ionophore A-23187, generated and released significantly more PGF2 alpha into the incubating solution than basal controls, but failed to exhibit changes in the basal output of PGE.(ABSTRACT TRUNCATED AT 250 WORDS)
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2497472&dopt=Abstract
J Pharmacobiodyn. 1988 Feb;11(2):88-94.
Effects of penetration enhancers on percutaneous absorption of nifedipine. Comparison between Deet and Azone.
Kondo S, Mizuno T, Sugimoto I.
Pharmaceuticals Research Center, Kanebo, Ltd., Osaka, Japan.
The influence of N, N-diethyl-m-toluamide (Deet) and 1-dodecylazacycloheptan-2-one (Azone), on skin permeability was examined for nifedipine (NP), taking into account their effects on the thermodynamic activity of the drug. The percutaneous absorption efficiency of NP was determined by measuring the drug concentration in rat plasma. Comparisons were made among NP suspensions in the enhancers to ensure equal thermodynamic activity. Azone increased NP penetration over that of propylene glycol (PG), while Deet produced a similar response to that of PG. The addition of a small amount of Deet to PG or diethyl sebacate (DES) provided for a rather large increase in NP penetration compared with that from PG or DES alone. The results of this study strongly suggest that Deet and Azone have different modes of action. Azone exerted a genuine effect on the skin and produced marked improvement in the penetration of NP. The effect of Deet was interesting as it was effective only in combination with other vehicles. Deet exhibits excellent solubilizing properties and penetrates the skin easily. Accordingly, it may be concluded that Deet functions simply as a cosolvent to produce saturated or supersaturated solutions of the active ingredient by its rapid disappearance from the vehicle, and thereby maximizes the thermodynamic activity of the drug.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3379568&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 ||