Myocardial uptake of thallium and rubidium during alterations in perfusion and oxygenation in isolated rabbit hearts.
The comparative effects of altered cellular function and coronary perfusion on myocardial 201Tl and 83Rb uptake were evaluated in three groups of isolated rabbit hearts having isovolumic contractions. Paired-indication dilution experiments were performed with 201Tl, 83Rb, and 111In-labeled albumin as an intravascular reference marker. In Group A hearts (n = 12), isotope transport was determined during control, hypoxia, and ischemia. In Group B hearts (n = 8), isotope transport was measured at control flow and again at a 50% and 80% reduction. In Group C hearts (n = 8) only 201Tl uptake was determined at control and following coronary reperfusion. Myocardial 201Tl and 83Rb transport were not significantly different and were proportional to flow. Although all interventions caused significant hemodynamic alterations, neither tracer was affected by hypoxia at constant flow. Thallium-201 permeation, however, was transiently decreased immediately after coronary reperfusion. We conclude that myocardial uptake of 201Tl and 83Rb are similar and directly related to flow, but do not reflect hypoxia induced cellular dysfunction.
D000818:Animals; D003326:Coronary Circulation; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D011817:Rabbits; D011868:Radioisotopes / Q000378:metabolism*; D012413:Rubidium / Q000378:metabolism*; D013793:Thallium / Q000378:metabolism*
D011868:Radioisotopes; D013793:Thallium; D012413:Rubidium; D010100:Oxygen