Journal of cardiovascular pharmacology and therapeutics
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J. Cardiovasc. Pharmacol. Ther. · Dec 2009
Comparative StudyNeither K+ channels nor PI3K/Akt mediates the vasodilative effect of nebivolol on different types of rat arteries.
Nebivolol is a highly selective beta(1)-adrenoceptor blocker with additional vasodilating properties. It has been shown that the nebivolol-induced vasorelaxation is nitric oxide (NO) dependent. The serine/ threonine protein kinase Akt phosphorylates endothelial cell NO synthase (eNOS) and enhances the ability of eNOS to generate NO. Previous studies have shown that the release of NO from the endothelium may be ascribed to the modulation of different types of K(+) channels. The current study was designed to determine whether K(+) channels or phosphatidylinositol-3-kinase (PI3K)/Akt may affect vasorelaxation induced by nebivolol in different rat arteries. ⋯ Nebivolol produced a concentration-dependent vasodilation in different rat arteries precontracted by PE or KCl. In the isolated rat aorta, carotid artery, femoral artery, and renal artery, neither K(+) channels nor PI3K/Akt pathway was involved in the relaxation induced by nebivolol.
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J. Cardiovasc. Pharmacol. Ther. · Sep 2009
Dose-related shortening of ventricular tachycardia cycle length after administration of the KATP channel opener bimakalim in a 4-day-old chronic infarct anesthetized pig model.
Potassium channel openers are known to act on potassium ATP-dependent channels in cardiac tissue. Such agents may exacerbate acceleration of acute ischemia-induced ventricular repolarization and aggravate arrhythmias. To test whether activation of K( ATP) channels during the healing period of myocardial infarction (MI) can still influence the electrophysiologic properties and the type of inducible arrhythmias, we investigated the effects of bimakalim (BIM) on sustained ventricular tachycardia (VT) 4 days after ligation of the left anterior descending (LAD) coronary artery in pigs. ⋯ Of 14 pigs receiving the highest BIM dosage, 3 revealed polymorphic VTs degenerating into ventricular fibrillation (VF). Our data suggest that high BIM doses may lead to faster and more aggressive pacing-induced reentrant VTs after subacute MI. This is consistent with the drug-induced acceleration of ventricular repolarization with shortening of MAP duration and refractoriness.
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J. Cardiovasc. Pharmacol. Ther. · Sep 2009
Comparative StudyThe effect of angiotensin-converting enzyme inhibitor on hemodynamic instability in patients undergoing cardiopulmonary bypass: results of a dose-comparison study.
Recently, hemodynamic instability including hypotension and its effect on the clinical outcome in patients treated with angiotensin-converting enzyme inhibitors (ACEIs) during coronary artery bypass graft (CABG) has been described. However, no analysis has examined the dose of ACEIs and its risk of hypotension. In this study, we tested the hypothesis that a higher dose of ACEIs could lead to increased episodes of hypotension. ⋯ Hemodynamic changes during CABG were observed to be directly proportional to the dosage of ACEIs prescribed preoperatively.
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J. Cardiovasc. Pharmacol. Ther. · Sep 2009
Editorial Biography Historical ArticleA salute to our founding editor-in-chief Bramah N. Singh, MD, DPhil, DSc, FRCP.
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J. Cardiovasc. Pharmacol. Ther. · Jun 2008
Comparative StudyIschemic postconditioning's benefit on reperfusion ventricular arrhythmias is maintained in the senescent heart.
The purpose of this study is to determine if postconditioning's beneficial effect on ventricular arrhythmias is maintained in elderly hearts. In elderly populations, the cardioprotective effects of ischemic preconditioning are lost. Previously, the authors observed that ischemic postconditioning markedly reduced reperfusion-induced ventricular arrhythmias in adult rats. ⋯ Here, the authors study young adult rats compared with senescent animals. They chose 24-month-old Fischer female rats as these rats are approaching the end of their normal life span. Unlike some studies that suggest that the benefits of preconditioning and postconditioning are lost in the elderly, their data show that antiarrhythmic protection conferred by postconditioning is present in both the young and old rats.