Drugs online research references
Arch Int Pharmacodyn Ther. 1994 Jan-Feb;327(1):25-39.
Vulnerability to ventricular fibrillation related to ischaemia: comparison of the acute effects of beta-blockers and calcium antagonists.
Aupetit JF, Timour Q, Freysz M, Loufoua-Moundanga J, Omar S, Chevrel G, Faucon G.
Department of Cardiology, Saint Joseph-Saint Luc Hospital Lyon, France.
A comparative evaluation of beta-blockers and calcium antagonists as protective agents against ventricular fibrillation related to myocardial ischaemia, was attempted in the pig heart in situ of anaesthetized, open-chest animals, subjected to a temporary complete occlusion of the left anterior descending coronary artery near its origin. This occlusion resulted in fibrillation occurring after a time depending on the vulnerability to the fibrillatory process. As this time to onset of fibrillation does normally not exceed a few minutes, its determination could be achieved repeatedly in the course of an experiment, in the absence and presence of drugs such as beta-blockers and calcium antagonists. When propranolol (0.05 mg/kg, i.v.) and verapamil (0.05 mg/kg, i.v.) abolished tachycardia produced by isoproterenol (0.25 micrograms/kg/min), the triggering of fibrillation was delayed in either case: in animals under atrial pacing at a rate close to the sinus rate on each determination, time to fibrillation was prolonged from about 160 to 400 sec by propranolol and from 160 to 640 sec by verapamil, with a return to control values within 60 min. Under ventricular pacing at a constant high rate (180 beats/min), no change was observed in time to fibrillation after propranolol (0.025 or 0.050 mg/kg), whereas verapamil, in the same conditions and in the same doses, multiplied this time by about 4 and 6, respectively. Consequently, propranolol and verapamil are likely to protect against fibrillation immediately after i.v. injection, but the protection due to propranolol is only indirect and a consequence of bradycardia which tends to increase the polarization of the muscular fibres, whereas verapamil adds to the same influence a direct preventive action by avoiding a cellular calcium overload in these fibres, which is responsible for the depolarization and fluctuations of their membrane potential.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7944825&dopt=Abstract
Arzneimittelforschung. 1998 Jan;48(1):47-51.
Effects of prostaglandin E2 on nitric oxide-mediated nonadrenergic noncholinergic relaxations in the guinea-pig tracheal muscle.
Baba K, Yoshida K, Hattori T, Kobayashi T.
3rd Department of Internal Medicine, Aichi Medical University Nagakute, Japan.
The effects of histamine, prostaglandin (PG) E2 and substance P (SP) on functions of nonadrenergic noncholinergic inhibitory (iNANC) nerves were examined in the guinea-pig tracheal muscle in vitro. In the presence of indometacin (10 mumol/l), atropine (2 mumol/l) and propranolol (1 mumol/l), field stimulation (FS) (1-80 Hz, 1 ms, 30 V for 45 s) was applied to the muscle strip under a condition where the same degree of contraction was produced by each agonist. Magnitudes of FS-induced relaxations were significantly smaller for the case of PGE2- or SP-produced contraction than those for the case of histamine-produced contraction. The FS-induced relaxations at lower stimulus frequencies (1-5 Hz) were suppressed by N omega-nitro-L-arginine methylester (L-NAME) (100 mumol/l) during histamine, although they were not affected by L-NAME during PGE2 or SP. Susceptibility of tracheal muscle to S-nitroso-N-acetylpenicillamine, a donor of nitric oxide (NO), was not different during PGE2 or histamine; it was significantly less during SP. FS-induced relaxation during histamine was suppressed by concomitant administration of PGE2 (10 nmol/l), however, not by concomitant administration of SP (30-100 nmol/l). These results suggest that PGE2 may inhibit release of NO from iNANC nerves in airways, whereas SP may suppress responsiveness of airway smooth muscle to the released NO. Results also indicate a possible involvement of these inflammatory mediators under conditions where airway iNANC nerves are impaired.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9522031&dopt=Abstract
Int J Impot Res. 1994 Jun;6(2):73-80.
Effects of ouabain on smooth muscle of the corpus cavernosum.
Oh CH, Kim SC.
Department of Urology, College of Medicine, Chung-Ang University, Seoul, Korea.
The effect of ouabain, an inhibitor of the membrane Na+/K+ ATPase, on smooth muscle of the corpus cavernosum was investigated. In an in vivo study using dogs, the intracorporeal pressures (ICPs) were measured before and during electrical stimulation of the cavernous nerve, and during nerve stimulation following intracorporeal injection of ouabain (1 x 10(-7) M). There was a significant drop of ICP following intracorporeal injection of ouabain (P < 0.001). In the in vitro study, ouabain increased the basal tone of the isolated cavernosal strip from the rabbit. When the strip was pretreated with tetrodotoxin (5 x 10(-7) M), phentolamine (1 x 10(-5) M), propranolol (1 x 10(-5) M) and atropine (1 x 10(-5) M), ouabain was still capable of contraction of the strip. The ouabain partly inhibited the relaxation effect of acetylcholine (1 x 10(-6) M), VIP (vasoactive intestinal polypeptide: 1 x 10(-8) M) and 2-chloro-adenosine (1 x 10(-6) M). The ouabain acts directly on the smooth muscle of the corpus cavernosum, increases its basal tone and diminishes the relaxation effect of acetylcholine, VIP and adenosine.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7951701&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 ||