title: Adenosine 5'-triphosphate induced dilation of human coronary microvessels in vivo.
abstract: OBJECTIVE
  This study was performed to compare the coronary microvascular response to adenosine 5'-triphosphate (ATP) with the response to adenosine in humans.
  
  
  METHODS
  Coronary blood flow velocity was determined using a Doppler flow wire. After intracoronary nitroglycerin infusion, intracoronary bolus injections of adenosine (20 microg) and ATP (20 microg) were performed to induce reactive hyperemia.
  
  
  METHODS
  Twenty-nine patients (23 men and 6 women, mean age: 63+/-9 years) with coronary artery disease and risk factors for coronary atherosclerosis were studied.
  
  
  RESULTS
  Coronary flow reserve in response to ATP was similar to that for adenosine (2.7+/-0.7 vs. 2.7+/-0.7). However, the duration of ATP-induced vasodilation was longer than that of adenosine-induced dilation (39+/-25 seconds vs. 26+/-12 seconds, p<0.0001). The coronary flow reserve obtained with either ATP or adenosine was significantly reduced in the interventioned arteries compared with non-stenosed arteries. The coronary flow reserve obtained with ATP was similar to that obtained with adenosine in both artery groups. The duration of the vasodilator effect of ATP was significantly greater than that of adenosine in both artery groups.
  
  
  CONCLUSIONS
  These results suggest that ATP induces maximal dilation of coronary microvessels, most likely through an endothelium-independent mechanism. The degradation of ATP to adenosine 5'-monophosphate (AMP) and adenosine, as well as the direct action of ATP on A2-adenosine receptors may be responsible for the dilation. We conclude that coronary flow reserve can be determined safely with intracoronary ATP administration.
authors.affiliation: First Department of Internal Medicine, Hiroshima University School of Medicine.
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: N
authors.initials: N
authors.lastname: Shiode
authors.forename: H
authors.initials: H
authors.lastname: Teragawa
authors.forename: H
authors.initials: H
authors.lastname: Hirao
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Yamagata
authors.forename: H
authors.initials: H
authors.lastname: Matsuura
authors.forename: G
authors.initials: G
authors.lastname: Kajiyama
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology; D003331:Coronary Vessels / Q000187:drug effects*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D000255:Adenosine Triphosphate; D000241:Adenosine