title: Inhibition of platelet aggregation by low concentrations of sodium fluoride. Significance of the intracellular calcium ion concentration.
abstract: Sodium fluoride activates platelets but its mechanism of action has not yet been completely identified. We examined the effect of a low concentration of sodium fluoride (which could not cause aggregation) on thrombin-induced changes in the intracellular calcium ion concentration ([Ca2+]i). In the presence of 1 mM extracellular Ca2+, preincubation with a low concentration of sodium fluoride decreased the peak of the thrombin-induced elevation of [Ca2+]i, when measured with aequorin. When [Ca2+] was measured using fura-2, preincubation caused no marked changes in its peak, but the later changes that were thought to mainly reflect extracellular Ca2+ influx were inhibited. The inhibitory mechanism of sodium fluoride appears to depend on reducing extracellular Ca2+ influx. Aequorin appears to reflect [Ca2+]i near the cell membrane and is thus easily affected by the extracellular Ca2+ influx.
authors.affiliation: First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kondo
authors.forename: C
authors.initials: C
authors.lastname: Kitada
authors.forename: A
authors.initials: A
authors.lastname: Yoshioka
authors.forename: H
authors.initials: H
authors.lastname: Sakane
authors.forename: T
authors.initials: T
authors.lastname: Kokawa
authors.forename: K
authors.initials: K
authors.lastname: Yasunaga
mesh_terms: D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003864:Depression, Chemical; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: D010975:Platelet Aggregation Inhibitors; D012969:Sodium Fluoride; D002118:Calcium