Uridine triphosphate (UTP) is released during cardiac ischemia.
BACKGROUND
Extracellular uridine triphosphate (UTP) stimulates vasodilatation, automaticity in ventricular myocytes and release of tissue-plasminogen activator (t-PA), indicating that UTP may be important in cardiac regulation. We took advantage of a recently developed quantitative assay for UTP to test the hypothesis that UTP is released in the circulation during cardiac ischemia.


METHODS
In ten pigs, a balloon catheter in the left anterior descending artery was introduced to induce ischemia. Samples were collected from the coronary sinus. Blood flow in the coronary sinus was assessed by a Doppler velocity transducer.


RESULTS
Plasma UTP levels increased early during ischemia and early after reperfusion (by 257+/-100 and 247+/-72%, p<0.05). Cardiac blood flow, ventricular arrhythmias and t-PA release were markedly increased at the same time points. In contrast, after 30 min, a second period of ischemia did not result in any significant increase of UTP or blood flow. Furthermore, ventricular arrhythmias were less frequent. UTP levels correlated with ventricular arrhythmia and blood flow. Similar results were found for ATP.


CONCLUSIONS
For the first time we have shown that UTP is released during cardiac ischemia. UTP released during ischemia may stimulate blood flow, arrhythmia and t-PA release.
Erlinge
David
D
Department of Cardiology, Lund University Hospital, S-221 85 Lund, Sweden. david.erlinge@kard.lu.se
Harnek
Jan
J
van Heusden
Catharina
C
Olivecrona
Göran
G
Jern
Sverker
S
Lazarowski
Eduardo
E
D000818:Animals; D005260:Female; D006321:Heart / Q000503:physiopathology; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D017202:Myocardial Ischemia / Q000201:enzymology* / Q000503:physiopathology; D015425:Myocardial Reperfusion; D012039:Regional Blood Flow; D013552:Swine; D010959:Tissue Plasminogen Activator / Q000097:blood; D014544:Uridine Triphosphate / Q000097:blood*
D010959:Tissue Plasminogen Activator; D014544:Uridine Triphosphate