The effects of isoproterenol on the isolated perfused rat heart
Abbott, D.; Lodola, A.
Research Communications in Chemical Pathology and Pharmacology 76(1): 125-128
1992
ISSN/ISBN: 0034-5164 PMID: 1518958 Document Number: 390587
In isolated hearts infused with up to 100 .mu.g/ml isoproterenol (ISP), there was only a transient effect on the frequency of contraction, and no effect on buffer flow through the heart. Infusion of hearts with 40-60 or 70-100 .mu.g/ml ISO produced an increase in the release of lactate dehydrogenase, but not creatinine kinase. Microscopic examination of hearts revealed myocyte separation and cytoplasmic vacuolation, of similar severity, in both control and ISO infused hearts; there was no necrosis. The data from this experiment are consistent with the view that ISO has little or no direct toxic effect on the heart. Since ISO is cardiotoxic in vivo, it is reasonable to suppose that ths toxicity is linked primarily to the pharmacological effects of the drug. However, our study does not exclude the possibility that under the stressed conditions prevailing in vivo following a challenge with ISO, the susceptibility of myocytes to a direct toxic effect of ISO may increase.