title: [In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery].
abstract: BACKGROUND
  The vasodilator effect of caffeine in animal models arteries has been demonstrated previously. However, studies with the same methodology using human arteries in vitro have not been performed.
  
  
  OBJECTIVE
  The in vitro vasoactive effects of caffeine was evaluated on human internal mammary arteries.
  
  
  METHODS
  Internal mammary artery rings were used (n = 20). Endothelial function was evaluated with acetylcholine at a concentration of 3.16 x 10 -6 M, nitroglycerine at cumulative concentrations of 10 -11 M to 10 -4 M and caffeine with cumulative concentrations of 10 -8 M to 10 -4 M.
  
  
  RESULTS
  Nitroglycerin produced a maximum relaxation percentage of 87.4 +/- 12.3%, caffeine a percentage of 86.9 +/- 21.0% in arteries with functional endothelium, and of 71.6 +/- 28.6% in arteries with endothelial dysfunction. No differences were detected among the three groups ( p=0.289). Similarly, no differences were found between EC 50 in arteries with functional endothelium (1.66 x 10 -5 +/-1.57 x 10 -5 M) and dysfunctional arteries (7.8 x 10 -5 +/-14.6 x 10 -5 M). Nitroglycerine proved more potent than caffeine (EC 50 = 4.3 x 10 -9 +/-4.4 x 10 -9 M) ( p=0.013).
  
  
  CONCLUSIONS
  Although nitroglycerin was a more potent vasodilator, caffeine had a strong arterial vasodilator effect regardless of endothelial function in human arteries.
authors: Laboratorio de Investigación en Función Vascular, Fundación Cardioinfantil, Instituto de Cardiología, Bogota, Colombia. decheverri@cardioinfantil.org
authors: Darío
authors: D
authors: Echeverri
authors: Félix R
authors: FR
authors: Montes
authors: Alexandra
authors: A
authors: Delgadillo
authors: Marcela
authors: M
authors: Beltrán
authors: Lorena
authors: L
authors: Buitrago
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis; D008323:Mammary Arteries / Q000187:drug effects*; D008875:Middle Aged; D009204:Myocardial Revascularization; D005996:Nitroglycerin / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D002110:Caffeine; D005996:Nitroglycerin