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 :

  • Effect of fluoride on the respiration rate of rat cardiac mitochondria.

    Fluoride by modifying the activity of mitochondrial enzymes may change their respiration rate. In this study NaF at concentrations 5, 10, and 50 µM had no effect on the State 3 respiration rate of rat cardiac mitochondria with succinate substrate. At a higher concentration of 7.5 mM, a significant (p<0.001)

  • Changes of certain oxidative, anti-oxidative and vascular function indexes of New Zealand rabbit exposed by high-fluoride.

    OBJECTIVE: To observe certain changes of oxidation, anti-oxidation and vascular function indexes of Application of New Zealand rabbit exposed by high-fluoride. METHODS: 20 male New Zealand rabbits were randomly divided into control group, drunk deionized water and feed basic diet. High-fat group, drunk deionized water and feed basic diet plus 0.5%

  • Heart deaths and fluoridation

    In the city of Antigo, Wisconsin, fluoridation of the public water supplies was initiated in 1949. ·It was discontinued in November 1960, and reinstituted in October 1965, A striking increase in the rate of deaths from heart disease occurred. in Antigo hnmediately following the introduction of fluoridation in 1949 and

  • Stimulation of cAMP accumulation in rat aorta and diaphragm by fluorine containing compounds

    Evidence is presented that accumulation of cAMP in isolated rat thoracic aorta and diaphragm is stimulated by several fluorine containing compounds (NaF, Na2PO3F (MFP) and SnF2). Time course experiments with NaF showed that maximal stimulation of cAMP accumulation was observed within 2.5 min. NaF and MFP produced significant increases in

  • Observations on electrocardiograms in a population living in a region with coal-burning-borne endemic fluorosis after comprehensive controls

    Objective: To observe the electrocardiogram (ECG) changes in the population living in the region with coal-burning-borne endemic fluorosis (EF for short) after comprehensive controls. Methods: People living in a region with coal-burning-borne EF in Bijie City of Guizhou Province were selected and then divided into 4 groups according to the

• Related FAN Content :

  • 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

  • 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 & 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 & 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 & 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