Force development of isoproterenol-damaged frog heart muscle in cyanide anoxia.
From recent experiments it is indicated that in frogs living at +25 degrees C the abnormal response to cyanide anoxia appears as soon as 4-5 hr after the first isoproterenol (IPR) injection, but the aneurysm does not appear until a few hours after the second injection of IPR. There is evidently a discrepancy between the biochemical and structural effects of IPR on the heart. The biochemical effects are probably transient as we have observed that a normal response to cyanide reappears a few weeks after the second IPR injection. It might thus be concluded that IPR causes derangement to the cells also in hearts without any visible lesions and demonstrated as a lowered resistance to histotixic anoxia. This effect precedes any structural damage if such should occur and is of a transient nature.
D000818:Animals; D001001:Anura; D001639:Bicarbonates / Q000494:pharmacology; D003486:Cyanides / Q000009:adverse effects*; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D006331:Heart Diseases / Q000139:chemically induced; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000139:chemically induced / Q000503:physiopathology*; D007545:Isoproterenol / Q000009:adverse effects*; D009200:Myocardial Contraction / Q000187:drug effects; D011894:Rana pipiens
D001639:Bicarbonates; D003486:Cyanides; D007545:Isoproterenol