title: Cyclic AMP and early contractile failure.
abstract: Cyclic AMP was measured in the isolated rat heart during anoxia in an attempt to demonstrate if this nucleotide is in any way related to the extent and rate of contractile failure. Isolated rat hearts were subjected to 15 min of normoxia followed by periods of between 1 and 300 sec of anoxia. Contractile force and its failure were monitored throughout. Tissue samples were obtained at various times using high-speed freeze-clamping techniques, and the frozen samples were taken for extraction and cAMP analysis. The results showed a significant increase in the levels of cAMP during the first 5 sec of anoxia, followed by a return to control levels as contractile activity fell to 40% of control. A second and significant increase in cAMP occurred during the following 60 sec. These results indicate major changes in cAMP levels during the first minute of anoxia-induced contractile failure and suggest that increases in this nucleotide may be related to extent and rate of contractile failure.
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
chemical_list: D000242:Cyclic AMP