EurekaMag.com logo
+ Site Statistics
References:
48,253,228
Abstracts:
22,798,842
+ Resolve Accession
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
Submit PDF Full TextSubmit PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrophysiologic effects of nicorandil a new antianginal agent on action potentials and membrane currents of rabbit atrioventricular node


, : Electrophysiologic effects of nicorandil a new antianginal agent on action potentials and membrane currents of rabbit atrioventricular node. Naunyn-Schmiedeberg's Archives of Pharmacology 335(5): 567-574

Electrophysiologic effects of nicorandil, a newly developed coronary vasodilator, on the atrioventricular (AV) node were studied using space-clamped small preparations of the rabbit AV node. At the concentrations of 10-6, 10-5 and 10-4 mol/l, this drug did not cause significant changes in the action potential characteristics including the spontaneous firing frequency, overshoot, maximum diastolic potential, maximum rate of depolarization and action potential duration. When the resting membrane potential of the AV node was obtained by a superfusion with verapamil and then nicorandil was added to the perfusate, no hyperpolarization was observed. This was in sharp contrast to the reported hyperpolarizing action of this drug on the atrial muscle, Purkinje fibres and vascular smooth muscle where the resting potential is much more negative. On the other hand, voltage clamp experiments using double microelectrode techniques revealed that 10-5 to 10-4 mol/l nicorandil increased the steady-state outward current at potentials positive to -40 mV and the steady-state inward current at potentials negative to -40 mV. Such a nicorandil-sensitive component of the steady-state current had an average reversal potential of -41.8 mV (n = 5). This component was considered to reflect changes in the time-independent background current, although, at more negative potential levels, it may partially reflect an increase in the hyperpolarization activated inward current (ih). Nicorandil, at the concentrations of 10-5 and 10-4 mol/l, increased the slow inward current (isi) by 10.8% (n = 5, p < 0.01). As the inactivation kinetics of the isi was not affected after the application of nicorandil, the increase in the isi may well be attributed to an increase in the fully activated isi (.hivin.isi). It was also shown that the increase in the isi was not mediated by neurotransmitters, as an increase of a similar degree was again observed in the presence of either propranolol or atropine. The apparent discrepancy between the effects of nicorandil on the action potential configuration and on the membrane currents may have resulted from cancellations between the inward increase in the isi and the outward increase in the background current during the action potential. Possible implications of these nicorandil effects in modifying AV conduction were discussed.

Order PDF Full Text

Close
Close

Click here to order any other PDF Full Text


Accession: 005349311

PMID: 2956524

DOI: 10.1007/bf00169126

PDF Full Text: Electrophysiologic effects of nicorandil a new antianginal agent on action potentials and membrane currents of rabbit atrioventricular node


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Other references

Gauzner, A.G.; Vilenskiĭ, I.G.; Fialkov, L.B.; Pirogov, N.I., 1981: Memorials to N. I. Pirogov. Klinicheskaia Khirurgiia: 78-79

Georgi, J. R., 1968: Estimation of erythrocyte loss in hookworm infection by whole-body 69Fe counting. The volume rate of erythrocyte loss suffered by dogs infected with Ancylostoma caninum was estimated by periodic measurement of whole-body Fe89 retention and erythrocyte Fe59 concentration. It was shown that the following assumptions were essentia...

Hubbard Dennis K.; Ramirez Wilson, 2006: Coral growth versus reef accretion; problems of scale, taphonomy and perception. The recent decline in coral reefs begs for geologic context to separate "unprecedented" decline from natural but cyclic change. The issue is not whether anthropogenic stress bears heavily on the present problem, but rather how reefs have...

Brown, R.C.; Blank, M.L.; Kostyu, J.A.; Osburn, P.; Kilgore, A.; Snyder, F., 1975: Analysis of tumor-associated alkyldiacylglycerols and other lipids during radiation-induced thymic leukemogenesis. Lipid composition of thymuses investigated during the development of thymic leukemogenesis induced by exposing C57BL/6J mice to gamma radiation led to the following conclusions. 1. Alkyldiacylglycerols, a class of lipids that are generally elevate...

Ghidoni, S.; Bruni, T.; Viotto, A.; Pulica, C.; Bruni, O.; Francia, L.; Tedoli, M.; Caleffi, G.; Busani, M.; Tenchini, P., 1995: Resection surgery in malignant neoplasms of the exocrine pancreas: our experience, 1987-1994. From 1987 to 1994, 24 patients underwent resection for pancreatic cancer; they represented 24% of all patients observed in that period. Surgical procedures were a pancreatoduodenectomy (PD) in 20 cases, a distal pancreatectomy in 4 cases, a pallia...

Novak, G.; Gallo, A.; Zai, C.C.; Meltzer, H.Y.; Lieberman, J.A.; Potkin, S.G.; Voineskos, A.N.; Remington, G.; Kennedy, J.L.; Levesque, D.; L.F.ll, B., 2010: Association of the orphan nuclear receptor NR4A1 with tardive dyskinesia. Recent evidence has identified the NR4A1 (NUR77, NGFI-B) gene as a strong candidate for involvement in tardive dyskinesia (TD). We have investigated the association of six single nucleotide polymorphisms within the NR4A family of genes with TD in...

Anonymous, 1959: Simazin slows down growth of anemones. At the Rosewarne Experimental Station, CIPC 1, 2 and 4 pounds per acre and fenuron, monuron and simazine 0.5, 1 and 2 pounds per acre were applied pre-em. to anemones. The higher rates of CIPC and 2 pounds per acre of monuron and simazine caused s...

Yasmin, R..; Pandey, BN.; Yasmin, A.., 1994: Studies on blood volume of a freshwater fish, Oreochromis mossambicus (Peters) in relation to body weight. Journal of Freshwater Biology. December; 64: 353-357

Kish, S.J.; Chang, L.J.; Dixon, L.M.; Robitaille, Y.; DiStefano, L., 1994: Cerebellar glutamate metabolizing enzymes in spinocerebellar ataxia type I. We measured the levels of three glutamate metabolizing enzymes, namely, glutamate dehydrogenase (GDH), aspartate aminotransferase (AAT), and glutamine synthetase (GS) in cerebellar and occipital cortices of nine patients with dominantly-inherited...

Liu, S.Q.; Ji, X.T.; Deng, L.J., 1987: Soil conditions for tea-planting in Zayu River Valley in Xizang. Yellow earths and diluvial soils suitable for tea have a base saturation of 37-88%, pH(H2O) of 4.74-6.94 and exchange acidity of 0.012-1.48 meq/100g soil in which exchangeable Al constitutes 2.2-98%. However, N supply in the soils is low due to hi...