1. The responsiveness of aortic rings from 4 and 12 week streptozotocin-induced diabetic rats to D600 (Gallopamil) and nifedipine was studied. 2. The sensitivity and responsiveness to D600 were significantly enhanced (P < 0.05; 5-test, ANOVA; 9 d.f.) only in the 4 week diabetic preparations precontracted with noradrenaline. 3. Nifedipine-induced relaxations were significantly enhanced (P < 0.05-0.01; t-test, ANOVA; 8-12 d.f.) in all the diabetic (4 and 12 weeks) aortic preparations precontracted with both noradrenaline (10(-7) mol/L) and KCl (40 mmol/L) when compared with controls. 4. D600, unlike nifedipine, did not produce significant relaxation of diabetic aortic preparations precontracted with KCl (40 mmol/L) at both week 4 and 12 of the disease when compared with controls. 5. These results suggest that there is differential responsiveness of streptozotocin diabetic rat aorta to D600 and nifedipine.
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Eur J Pharmacol
July 2016
Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico. Electronic address:
Unlabelled: Membrane depolarization of airway smooth muscle (ASM) opens L-type voltage dependent Ca(2+) channels (L-VDCC) allowing Ca(2+) entrance to produce contraction. In Ca(2+) free conditions Na(+) permeates through L-VDCC in excitable and non-excitable cells and this phenomenon is annulled at µM Ca(2+) concentrations. Membrane depolarization also induces activation of Gq proteins and sarcoplasmic reticulum Ca(2+) release.
View Article and Find Full Text PDFClin Toxicol (Phila)
November 2014
Ontario and Manitoba Poison Centre, Toronto, ON , Canada.
Context: Calcium channel blocker poisoning is a common and sometimes life-threatening ingestion.
Objective: To evaluate the reported effects of treatments for calcium channel blocker poisoning. The primary outcomes of interest were mortality and hemodynamic parameters.
Eur J Pharmacol
December 2013
Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, México.
Sarcoplasmic reticulum Ca(2+) refilling (SRREF) is crucial to sustain the agonists induced airway smooth muscle contraction. Nevertheless, its mechanisms have not been clearly described yet, although L-type voltage dependent, store operated, receptor operated channels and the Na(+)/Ca(2+) exchanger in its reverse mode (NCXREV) have been proposed as Ca(2+) handling proteins participating in this process. We found that in guinea pig and bovine tracheal smooth muscle, SRREF induced by caffeine was completely abolished by thapsigargin, even in the presence of Bay K8644, an activator of the L-type Ca(2+) channel.
View Article and Find Full Text PDFEur J Pharmacol
January 2012
Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, Mexico.
The Na(+)/Ca(2+)exchanger (NCX) principal function is taking 1 Ca(2+) out of the cytoplasm and introducing 3 Na(+). The increase of cytoplasmic Na(+) concentration induces the NCX reverse mode (NCX(REV)), favoring Ca(2+) influx. NCX(REV) can be inhibited by: KB-R7943 a non-specific compound that blocks voltage-dependent and store-operated Ca(2+) channels; SEA0400 that appears to be selective for NCX(REV), but difficult to obtain and SN-6, which efficacy has been shown only in cardiomyocytes.
View Article and Find Full Text PDFCurr Med Chem
December 2011
Department of Physiology, University of Debrecen, Nagyerdei krt. 98. H-4012 Debrecen, Hungary.
Action potential voltage-clamp (APVC) is a technique to visualize the profile of various currents during the cardiac action potential. This review summarizes potential applications and limitations of APVC, the properties of the most important ion currents in nodal, atrial, and ventricular cardiomyocytes. Accordingly, the profiles ("fingerprints") of the major ion currents in canine ventricular myocytes, i.
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