The natriuretic effect of Ca(2+) channel blockers has been attributed to hemodynamic changes and to poorly defined direct tubular effects. To test the possibility that verapamil may inhibit Na(+) reabsorption at the distal tubule, its effect on transepithelial Na(+) transport in aldosterone-stimulated A6 cells was determined. Cells were grown on permeable supports, and short-circuit current (I(...

The acute hemodynamic effects of an i.v. bolus of verapamil, 0.1 mg/kg or 0.06-0.075 mg/kg, were examined by serial radionuclide studies in 46 patients with coronary artery disease. In 20 patients with ejection fractions (EFs) greater than 35% (group 1A), verapamil, 0.1 mg/kg given over 1-11/2 minutes, had a biphasic effect: first, a transient decrease in EF accompanied by increased left ventri...

Verapamil is used in the treatment of hypertension, angina pectoris, and atrial fibrillation. Recently, several studies have demonstrated that verapamil increased the optic nerve head blood flow and improved the retrobulbar circulation. All these show that verapamil is potentially useful for ophthalmic treatment. Thus, the aim of this study is to investigate whether verapamil could protect huma...

To determine the effect of verapamil on experimental duodenal ulcer, pathologic assessment and secretory study were performed in the rats with ulcerogenic dose of cysteamine. The cysteamine increased gastric acid secretion and produced double duodenal ulcers at the proximal protion of the duodenum. Intramuscular injection of verapamil, 3 hours later, produced a significant decreased in gastric ...

OBJECTIVE Ions, particularly calcium ions, play an important role in ischemia-reperfusion cell injury. In this study, we investigated the action of verapamil on the mitochondrial function of kidneys submitted to ischemia without blood reperfusion in order to study isolated early and late ischemic effects. MATERIALS AND METHODS 44 rats were submitted to bilateral warm renal ischemia for 30 min...

Effect of verapamil, a Ca2+ channel blocker, on the contractions in the intestinal smooth muscle of taenia isolated from guinea-pig caecum was examined. In normal medium, 10 mM-80 mM KCl or 10(-7) M-10(-5) M carbachol induced a transient contraction followed by a sustained one. When the muscle strips were treated with a Ca2+-free solution for 2 min, these stimulants failed to induce contraction...

Retinal pigment epithelial (RPE) cells transport a variety of solutes, but the capacity of human RPE cells to transport drugs and xenobiotics is not well understood. As an initial step to address this issue, we have examined human RPE transport of verapamil. Transport of [3H]verapamil was measured in two human RPE cell lines (RPE/Hu and ARPE-19) grown to confluence on 12-well culture plates. Ve...

The characteristics of reentrant circuits during short duration ventricular fibrillation (SDVF; 20 s in duration) and the role of Ca(++) and rapid-activating delayed rectifier potassium currents during long duration ventricular fibrillation (LDVF; up to 10 min in duration) were investigated using verapamil and sotalol. Activation mapping of the LV epicardium with a 21 × 24 electrode plaque was ...

BACKGROUND Peptic ulcer is a common ailment for which over production of gastric acid is the main cause. This study was undertaken to find out the effects of Calcium channel blocker Verapamil and Cimetidine on volume and acidity of Carbacol induced gastric section, free and total acidity of carbachol induced gastric secretion and their effects were also compared. METHODS Thirty rabbits of loc...

P-glycoprotein (P-gp) is a major efflux transporter contributing to the efflux of a range of xenobiotic compounds at the blood-brain barrier (BBB). In the present study, we evaluated the P-gp function at the BBB using positron emission tomography (PET) in nonhuman primates. Serial brain PET scans were obtained in three rhesus monkeys after intravenous administration of [(11)C]verapamil under co...