title: The similarity between aspirin treatment and the lack of response to epinephrine and the frequency of aspirin resistance in healthy males.
abstract: OBJECTIVE
  The lack of response of platelets against epinephrine has been discovered with a frequency of 14% to 40% in previous studies. There are studies that have demonstrated the effect of aspirin on platelets may resemble the lack of response to epinephrine. In this study, the extent of the effects of aspirin treatment on aggregation and secretion in healthy males with a lack of response to epinephrine and the frequency of aspirin resistance were investigated.
  
  
  METHODS
  Blood samples were collected at the beginning and at the end of a 10-day aspirin usage in 52 healthy males. Epinephrine, adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and thrombin aggregations, and adenosine triphosphate (ATP) secretion were studied. Participants were assigned to nonresponder (<20%), semiresponder (20%-60%), and responder (>60%) groups, depending on their maximum aggregation responses to epinephrine. Participants who displayed an aggregation to AA at the end of the aspirin treatment were accepted to be aspirin resistant.
  
  
  RESULTS
  Of the 52 participants, 4 were found to be nonresponders and 3 of 52 of the participants were found to be semiresponders. Although the lack of response to epinephrine and aspirin treatment displayed similarities in aggregations using epinephrine, ADP, collagen, and thrombin, they differed in aggregations using AA and for ATP secretion. The ratio of aspirin resistance was determined to be 4:52.
  
  
  CONCLUSIONS
  The observation of AA aggregation in the participants with a lack of response to epinephrine demonstrates that epinephrine nonresponse cannot substitute aspirin treatment. The fact that aspirin resistance is observed in healthy males supports the view that aspirin resistance exists even before the first usage.
authors.affiliation: Department of Biophysics, Ege University, Faculty of Medicine, Izmir, Turkey. esagdilek@hotmail.com
authors.forename: Engin
authors.initials: E
authors.lastname: Sagdilek
authors.forename: Ahmet
authors.initials: A
authors.lastname: Korkmaz
authors.forename: Sukru
authors.initials: S
authors.lastname: Oter
authors.forename: Ferit
authors.initials: F
authors.lastname: Avcu
authors.forename: Turgut
authors.initials: T
authors.lastname: Topal
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozler
authors.forename: Bulent
authors.initials: B
authors.lastname: Uysal
authors.forename: Oral
authors.initials: O
authors.lastname: Nevruz
authors.forename: Cengiz
authors.initials: C
authors.lastname: Beyan
authors.forename: Kasim
authors.initials: K
authors.lastname: Ozluk
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D001241:Aspirin / Q000008:administration & dosage*; D004351:Drug Resistance; D004837:Epinephrine / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D000316:Adrenergic alpha-Agonists; D010975:Platelet Aggregation Inhibitors; D001241:Aspirin; D004837:Epinephrine