EurekaMag.com logo
+ Site Statistics
References:
52,725,316
Abstracts:
28,411,598
+ Search Articles
+ 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
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrophysiological effects of flecainide on guinea pig ventricular muscle in high extracellular potassium concentration acidosis and hypoxia


Japanese Heart Journal 28(4): 539-554
Electrophysiological effects of flecainide on guinea pig ventricular muscle in high extracellular potassium concentration acidosis and hypoxia
The electrophysiological effects of flecainide on the action potential were examined in guinea pig ventricular muscles using microelectrode recording methods. Under the control conditions, flecainide (0.5-1 .mu.g/ml) did not alter the resting potential, action potential duration (APD) or effective refractory period (ERP). The major effect of flecainide was on maximum upstroke velocity (.ovrhdot.Vmax), which was depressed in a dose-dependent manner. In high [K+] medium (potassium concentration=10 mM), .ovrhdot.Vmax was depressed by 16.8 at a concentration of 1.0 .mu.g/ml (8.8% in normal [K+]o). In metabolic acidosis (pH = 6.89), it was depressed by 15.7% at the same concentration of the drug (8.3% in normal condition). The changes in ERP and ERP/APD90% in high [K+]o and metabolic acidosis were not significantly different from the normal condition. After hypoxic perfusion for 15 min, .ovrhdot.Vmax depression by flecainide was 16.3% (7.4% in control medium). The increase of ERP/APD90% was also greater in hypoxia. These data indicate that the most prominent effect of flecainide is .ovrhdot.Vmax depression which is enhanced under the high K+, acidic and hypoxic conditions. Therefore, it is suggested that flecainide may be most effective for ventricular arrhythmias occurring in myocardial ischemia.


Accession: 005349569



Related references

Electrophysiological effects of flecainide on guinea pig ventricular muscle in high [K+]o, acidosis and hypoxia. Japanese Heart Journal 28(4): 539-554, 1987

Electrophysiological and inotropic effects of Coenzyme Q10 on guinea pig ventricular muscle depolarized by potassium under hypoxia. Japanese Heart Journal 23(6): 961-974, 1982

Effects of high potassium acidosis hypoxia and glucose lack on internal longitudinal resistance in ventricular muscle. Physiologist 27(4): 217, 1984

The combined effects of hypoxia high potassium and acidosis on the intracellular sodium activity and resting potential in guinea pig papillary muscle. Circulation Research 58(2): 249-256, 1986

Use- and concentration-dependent effects of flecainide in guinea pig right ventricular muscle. Journal of Cardiovascular Pharmacology 24(2): 177-183, 1994

Interaction of acidosis and increased extracellular potassium on conduction velocity in guinea pig ventricular muscle. Japanese Circulation Journal 47(8): 934, 1983

Interaction of acidosis and increased extracellular potassium on action potential characteristics and conduction in guinea pig ventricular muscle. Circulation Research 51(5): 614-623, 1982

Effects of acidosis on extracellular potassium accumulation and surface ph in isolated ischemic guinea pig papillary muscle. Journal of Physiology (Cambridge) 429: 110P, 1990

Combined effects of hypoxia, hyperkalemia and acidosis on membrane action potential and excitability of guinea-pig ventricular muscle. Journal of Molecular and Cellular Cardiology 16(3): 247-259, 1984

Effects of hypoxia elevated potassium and acidosis on the potency of verapamil diltiazem and nifedipine in the guinea pig isolated papillary muscle. British Journal of Pharmacology 98(3): 937-949, 1989