PARTITION OF TL-201 IN ISOLATED MYOCARDIAL TISSUE OF RATS PREVIOUSLY INJECTED AT REST OR AFTER EXERCISE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 20  (11) , 1136-1141
Abstract
[Myocardial scintigraphy after i.v. injection of 201Tl is valuable in the noninvasive diagnosis of myocardial infarction and ischemia.] The kinetics and distribution of 201Tl isolated myocardial tissue of rats injected i.v. with this radionuclide are compared at rest and after exercise (2 h of forced swimming). At 1/2 and 3 h after injection, a myocardial segment was obtained and subjected to continuous washout, with the radioactivity remaining in the tissue recorded each 10 s for 1 h. There were 4 groups of 10 animals each. A 3-compartment model (extracellular, main intracellular and subcellular) described adequately the kinetics of 201Tl. In the groups studied 1/2 h after 201Tl injection the most dramatic effect of exercise was a translocation of 201Tl into the subcellular compartment. The change was also present but less marked in samples from exercised rats obtained 3 h after 201Tl injection, which suggests a transition to the resting stage. The possibility of structural subcellular differences in myocardial uptake is suggested for 201Tl in clinical images visualized after exercise and at rest.