Open AccessIn vivo assessment of coronary flow and cardiac function after bolus adenosine injection in adenosine receptor knockout mice
Author(s) -
Teng Bunyen,
Tilley Stephen L.,
Ledent Catherine,
Mustafa S. Jamal
Publication year - 2016
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12818
Subject(s) - adenosine , medicine , adenosine receptor , cardiology , blood flow , ventricle , cardiac function curve , stroke volume , bolus (digestion) , heart rate , agonist , coronary circulation , anesthesia , receptor , blood pressure , heart failure
Bolus injections of adenosine and the A 2A adenosine receptor ( AR ) selective agonist (regadenoson) are used clinically as a substitute for a stress test in people who cannot exercise. Using isolated tissue preparations, our lab has shown that coronary flow and cardiac effects of adenosine are mostly regulated by the AR subtypes A 1 , A 2A , and A 2B . In this study, we used ultrasound imaging to measure the in vivo effects of adenosine on coronary blood flow (left coronary artery) and cardiac function in anesthetized wild‐type, A 1 knockout ( KO ), A 2A KO, A 2B KO, A 3 KO, A 1 , and A 3 double KO (A 1/3 DKO) and A 2A and A 2B double KO (A 2A/2B DKO) mice in real time. Echocardiographic and Doppler studies were performed using a Visualsonic Vevo 2100 ultrasound system. Coronary blood flow ( CBF ) baseline data were obtained when animals were anesthetized with 1% isoflourane. Diameter (D) and velocity time integral ( VTI ) were measured on the left coronary arteries (CBF = ((π/4) × D 2 × VTI × HR)/1000). CBF changes were the highest within 2 min of injection (about 10 mg/kg). Heart rate, cardiac output, and stroke volume were measured by tracing the left ventricle long axis. Our data support a role for the A 2 AR in CBF and further support our conclusions of previous studies from isolated tissues. Adenosine‐mediated decreases in cardiac output and stroke volume may be A 2B and/or A 3 AR ‐mediated; however, the A 1 and A 2 AR s also play roles in overall cardiac function. These data further provide a powerful translational tool in studying the cardiovascular effects of adenosine in disease states.