Abstract
Acute fluoride intoxication increases intracellular calcium (Cai), manifested by increased twitch tension in cardiac muscle, and by potassium efflux (mediated by Ca2+-dependent K+ channels) in fluoridated erythrocytes. Fluoride, like isoproterenol, stimulates adenylate cyclase, and could increase Cai via the effects of cAMP on Ca2+ channels. However, while the inotropic effects of fluoride mimicked isoproterenol in rat atria, their effects on the time course of isometric contraction were quite different. In addition, acetylcholine negated isoproterenol’s effect on twitch tension but did not modulate the effects of fluoride. Further, the Ca2+ channel antagonist verapamil had no effect on fluoride-stimulated K+ efflux from erythrocytes. Fluoride also inhibits Na+-K+ ATPase, and increases intracellular Na+, so could increase Cai via Na+-Ca2+ exchange. Lanthanum, which blocks Na+-Ca2+ exchange, blocks fluoride-induced K+ efflux in erythrocytes. We conclude that the effects of fluoride on adenylate cyclase are not important in intact tissue, and that inhibition of Na+-K+ ATPase and subsequent Na2+-Ca2+ exchange may be the mechanism of increased Cai in acute fluoride toxicity.
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Interactive effect of arsenic and fluoride on cardio-respiratory disorders in male rats: possible role of reactive oxygen species.
Epidemiological evidence demonstrates positive correlation between environmental and occupational arsenic or fluoride exposure and risk to various cardio-respiratory disorders. Arsenic-exposure has been associated with atherosclerosis, hypertension, cerebrovascular diseases, ischemic heart disease, and peripheral vascular disorders, whereas Fluoride-exposure manifests cardiac irregularities and low blood pressure (BP). Present study aims to study
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Chronic fluoride toxicity and myocardial damage: antioxidant offered protection in second generation rats
This experiment was designed to investigate the extent of peroxidative changes and histological alterations in the myocardium of rats exposed to high fluoride for two generations, in addition to ameliorative role of selenium and vitamin E on the above indices. Adult albino Wistar rats were given fluoride through drinking water
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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,
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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,
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Fluoride stimulation of slow Ca2+ current in cardiac muscle.
Fluoride, a known activator of the adenylate cyclase in broken-cell preparations of heart and other tissue [21, 22] was tested for its ability to act as a positive inotropic agent in cardiac muscle and for its ability to concomitantly induce Ca2+ channels. The induction of slow Ca2+ channels was tested
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