title: Subcellular and molecular mechanisms of the effects of cardiac glycosides and angiotensin-converting enzyme inhibitors on contractile function and energy conversion in myocardial myofibrils under normal conditions and during acute cardiac insufficiency.
abstract: Experiments on skinned and hybrid myocardial fibers isolated from normal dogs and animals subjected to 120-min occlusion of the anterior interventricular branch of the coronary artery showed that in contrast to cardiac glycosides, angiotensin-converting enzyme inhibitors suppress contractile ability of myocardial myofibrils in a dose-independent manner within the concentration range of 10(-12)-10(-4)M. This effect is accompanied by a decrease in fiber relaxation rate most pronounced in the presence of captopril. Actin, the major protein of fine filaments is the target for b-acetyldigoxin, K-strophanthin, captopril, enalapril, and trandolapril in myocardial myofibrils. During coronary occlusion, the inhibitors of angiotensin-converting enzyme induce structural and conformational changes in actin that decrease efficiency of contraction. The data obtained cast doubt on advisability of therapeutic use of angiotensin-converting enzyme inhibitors in the therapy of myocardial infarction, especially in its early period.
authors.affiliation: Research Center of Medical Biophysics and Application of New Biomedical Technologies, Georgian Ministry of Health, Tbilisi.
authors.forename: G V
authors.initials: GV
authors.lastname: Sukoyan
authors.forename: V N
authors.initials: VN
authors.lastname: Karsanov
authors.forename: D R
authors.initials: DR
authors.lastname: Tatulashvili
authors.forename: E I
authors.initials: EI
authors.lastname: Gochua
authors.forename: T G
authors.initials: TG
authors.lastname: Samsonidze
authors.forename: N V
authors.initials: NV
authors.lastname: Karsanov
mesh_terms: D000199:Actins / Q000737:chemistry; D000208:Acute Disease; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D002301:Cardiac Glycosides / Q000037:antagonists & inhibitors*; D004285:Dogs; D004734:Energy Metabolism; D066298:In Vitro Techniques; D008958:Models, Molecular; D009200:Myocardial Contraction / Q000187:drug effects*; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D009210:Myofibrils / Q000187:drug effects* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D000199:Actins; D000806:Angiotensin-Converting Enzyme Inhibitors; D002301:Cardiac Glycosides