title: Sevoflurane does not inhibit human platelet aggregation induced by thrombin.
abstract: BACKGROUND
  Sevoflurane reportedly inhibits adenosine diphosphate-induced platelet aggregation by suppressing thromboxane A2 formation. The increase in intracellular calcium concentration that fosters platelet aggregation, however, is also induced by other cell signaling pathways, such as activation of the production of inositol 1,4,5-triphosphate by thrombin. The current study aimed to clarify the net influence of sevoflurane on thrombin-induced platelet aggregation.
  
  
  METHODS
  Washed platelets were stimulated by thrombin after incubation with 0.5, 1.0, or 1.5 mM sevoflurane, halothane, or isoflurane. Aggregation curves were measured by an aggregometer. Intracellular calcium concentration was measured fluorometrically using fura-2. Calcium mobilization via plasma membrane calcium channels and the dense tubular system was assessed differentially. Intracellular inositol 1,4,5-triphosphate was measured by radioimmunoassay.
  
  
  RESULTS
  Halothane significantly suppressed aggregation ratios at 5 min compared with those in controls (89 +/- 7%) to 71 +/- 10% (1.0 mM) and 60 +/- 11% (1.5 mM) and the increase in intracellular calcium concentration (controls, 821 +/- 95 nM vs. 440 +/- 124 nM [1.0 mM] or 410 +/- 74 nM [1.5 mM]). Halothane also significantly inhibited release of calcium from the dense tubular system (controls, 220 +/- 48 nM vs. 142 +/- 31 nM [1.0 mM]). Neither sevoflurane nor isoflurane produced a net change in aggregation ratios, intracellular calcium concentration, or calcium mobilization. Halothane (1 mM) significantly suppressed inositol 1,4,5-triphosphate concentrations, whereas neither 1 mM isoflurane nor 1 mM sevoflurane had any effect.
  
  
  CONCLUSIONS
  Although sevoflurane has been reported to inhibit human platelet aggregation induced by weak agonists such as adenosine diphosphate, it does not inhibit human platelet aggregation induced by strong agonists such as thrombin.
authors.affiliation: Department of Anesthesiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nozuchi
authors.forename: T
authors.initials: T
authors.lastname: Mizobe
authors.forename: H
authors.initials: H
authors.lastname: Aoki
authors.forename: N
authors.initials: N
authors.lastname: Hiramatsu
authors.forename: K
authors.initials: K
authors.lastname: Kageyama
authors.forename: F
authors.initials: F
authors.lastname: Amaya
authors.forename: K
authors.initials: K
authors.lastname: Uemura
authors.forename: T
authors.initials: T
authors.lastname: Fujimiya
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D006221:Halothane / Q000494:pharmacology; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000097:blood; D007530:Isoflurane / Q000494:pharmacology; D008738:Methyl Ethers / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D000077149:Sevoflurane; D013917:Thrombin / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D010975:Platelet Aggregation Inhibitors; D000077149:Sevoflurane; D015544:Inositol 1,4,5-Trisphosphate; D007530:Isoflurane; D013917:Thrombin; D002118:Calcium; D006221:Halothane