Further evidence for the role of adenosine in hypercapnia/acidosis-evoked coronary flow regulation.
Experiments were performed on isolated, nonworking rat hearts perfused at constant pressure according to the Langendorff technique to evaluate the role of adenosine in hypercapnia-evoked coronary vasodilation. Hypercapnia/acidosis resulted in increases in heart rate and coronary flow rates in conjunction with a decrease in ventricular contractile tensions. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA, 10 microM) reduced the heart rate and enhanced CO2-evoked increases in coronary vascular flow. 5-Iodotubercidin (1 microM), an inhibitor of adenosine kinase, caused a reduction in heart rate and enhanced coronary flow rates during hypercapnic perfusion. Adenosine deaminase (1 U/ml) significantly attenuated CO2-evoked increases in coronary vascular flow. These results extend those of previous investigations implicating adenosine in the regulation of coronary flow during conditions of respiratory or metabolic acidosis.
Phillis
J W
JW
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA. jphillis@med.wayne.edu
O'Regan
M H
MH
Song
D
D
D000138:Acidosis / Q000503:physiopathology*; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000241:Adenosine / Q000502:physiology*; D058892:Adenosine Deaminase Inhibitors; D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006935:Hypercapnia / Q000503:physiopathology*; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014372:Tubercidin / Q000031:analogs & derivatives / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D058892:Adenosine Deaminase Inhibitors; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D002245:Carbon Dioxide; C034214:5-iodotubercidin; C010192:9-(2-hydroxy-3-nonyl)adenine; D000225:Adenine; D000241:Adenosine; D014372:Tubercidin