Abstract

The modulatory actions of fluoride on the function of the dihydropyridine-sensitive (L-type) Ca2+ channel were studied in rabbit cardiac myocytes. In cell-attached voltage-clamp experiments, using barium as the charge carrier, fluoride increased the activity of the Ca2+ channel dose-dependently. Low concentrations (<10 mM) of fluoride increased the number of traces with channel activities, and decreased the number of traces without channel activities, resulting in a net increase in the open-channel probability. The effect of 5 mM fluoride on the Ca2+ channel was inhibited by the presence of non-hydrolyzable guanosine diphosphate analog in the cell. On the other hand, high concentrations (>10 mM) of fluoride increased the open-channel duration, resulting in a marked increase in open-channel probability. A pretreatment of myocytes with a phosphatase inhibitor, okadaic acid, virtually abolished the additional effect of fluoride on the open-channel duration or open probability. A concentration of up to 75 mM fluoride had no effect on the Ca2+-channel activity when the myocytes were pretreated with a potent inhibitor of protein kinases, indicating that fluoride increased the Ca2+- channel activity via modulation of the phosphorylation state of the myocyte or the channel protein alone.

• Related Studies :

  • Further evidence for the involvement of cAMP in central blood pressure regulation

    In order to test the hypothesis that the activity of cardiovascular centres is determined by their content of cAMP a number of drugs which influence the activity of either phosphodiestase or adenylcyclase were injected in doses of 100-1000 mug/kg into the lateral cerebral ventricle of cats. The effects on blood

  • Telangiectasia in aluminum workers: a follow up.

    The cause of telangiectasia was investigated in aluminum (7429905) workers. Physical examinations, biochemical tests, and hemodynamic measurements were performed on 50 current workers, 23 cases of telangiectasia, and 27 comparisons to determine the presence of metabolic disorders. Data was obtained by a self administered questionnaire and by physical examination. Medical

  • Effects of melatonin and epiphyseal proteins on fluoride-induced adverse changes in antioxidant status of heart, liver, and kidney of rats

    Several experimental and clinical reports indicated the oxidative stress-mediated adverse changes in vital organs of human and animal in fluoride (F) toxicity. Therefore, the present study was undertaken to evaluate the therapeutic effect of buffalo (Bubalus bubalis) epiphyseal (pineal) proteins (BEP) and melatonin (MEL) against F-induced oxidative stress in heart,

  • The clinical features of 160 cases of acute sodium silicon fluoride poisoning.

    160 cases of acute sodium silicon fluoride poisoning due to accidental intake are reported in this paper. Owing to the great amount of the chemical taken, the onset was abrupt and the digestive symptoms were prominent and severe. Twelve cases had acute gastritis or acute ulceration as shown by gastroscopy.

  • Acute fluoride poisoning alters myocardial cytoskeletal and AMPK signaling proteins in rats

    BACKGROUND:  Our previous findings revealed that increased oxidative stress, apoptosis and necrosis were implicated in acute fluoride (F-) induced cardiac dysfunction apart from hypocalcemia and hyperkalemia. Cardiac intermediate filaments (desmin and vimentin) and cytoskeleton linker molecule vinculin plays an imperative role in maintaining the architecture of cardiac cytoskeleton. In addition,

• Related FAN Content :

  • Fluoride & Electrocardiogram Abnormalities

    An electrocardiogram (ECG) is a diagnostic test that measures the electrical activity of the heart. An ECG can reveal heart rate, heart rhythym (i.e. steady or irregular), and the strength and timing of the heart’s natural electrical signals. ECGs are described in terms of “waves” (e.g. amplitude and duration). Problems

  • Fluoride & Arteriosclerosis

    Healthy arteries are flexible and elastic, allowing efficient transfer of blood and nutrients from the heart to the rest of the body. Arteriosclerosis refers to a stiffening of the arteries, including loss of elasticity. This is a slow, progressive disease that may begin early in life from damage to the

  • Fluoride & Arterial Calcification

    The major change involved with cardiovascular disease is development of atherosclerosis in critical arteries, which is partially characterized by vascular calcification. The level of coronary artery calcification is thought to be the most important indicator of future cardiovascular events. Increased arterial calcifications have frequently been reported in those with skeletal fluorosis

  • Fluoride, Blood Pressure and Hypertension

    Individuals with blood pressure readings that exceed 140/90 are considered hypertensive. Hypertension can increase the risk of stroke, heart attack, heart failure, aortic aneurysms, and peripheral arterial disease. An association between increased fluoride in ground water and increased prevalence of hypertension has been observed, especially among adult males (Amini et

  • Fluoride & Myocardial Damage

    Structural damage to the heart resulting from fluoride toxicity has been observed in numerous human and animal studies. The general features of this damage include cloudy swelling, vacuolization or vacuolar degeneration, hemorrhages, interstitial edema, fibrous necrosis, dissolution of nuclei, and thickening of the vessel walls in the heart muscle (Basha