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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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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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
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Systematic impacts of fluoride exposure on the metabolomics of rats.
Highlights The risk of chronic endemic fluorosis exists in many countries and regions. Comprehensive metabolomic analysis was used to study the effects of fluoride. Multivariate statistics were used to detect metabolite profile changes. Fluoride exposure caused amino acid, fatty acid, and energy metabolism disorders. Fluoride exposure caused oxidative stress,
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Protective effect of quercetin against sodium fluoride induced oxidative stress in rat's heart
The antioxidative and cardioprotective properties of quercetin were investigated against sodium fluoride (NaF) induced oxidative stress in rat hearts. Experimental rats were divided into five groups. The first group served as the untreated (normal) control. The second group received NaF at a dose of 600 ppm through drinking water for
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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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