title: Cardiac sarcoplasmic reticular function in rats with chronic heart failure following myocardial infarction.
abstract: Sarcoplasmic reticular function of rats with chronic heart failure (CHF) following coronary artery ligation was examined. The coronary artery ligation produced 43% infarction of the left ventricle and increased left ventricular end-diastolic pressure 8 weeks after the operation, suggesting the development of CHF by this period. The developed force transients of the skinned fiber of coronary artery-ligated rats were decreased when the skinned fiber was preloaded for 0.25-0.5 min with 10(-5)M Ca2+ (53-70%) and when preloaded with 10(-6)M Ca2+ and then exposed to 0.1-1 mM caffeine (39-87%). The results suggest that the rate of Ca2+ uptake by the sarcoplasmic reticulum (SR) and its ability to release Ca2+ were reduced in the failing heart. [3H]Ryanodine binding activities in homogenates and SR-enriched fractions were significantly reduced in the coronary artery-ligated group (32% and 21%, respectively). The results suggest that the amount of Ca2+ released from SR decreased due to decreased Ca2+ uptake rate of SR and down-regulation of the SR Ca(2+)-release channel, which contributes to cardiac dysfunction in failing hearts following acute myocardial infarction.
authors.affiliation: Department of Pharmacology, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Yamaguchi
authors.forename: A
authors.initials: A
authors.lastname: Sanbe
authors.forename: S
authors.initials: S
authors.lastname: Takeo
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics; D002462:Cell Membrane / Q000378:metabolism; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D006333:Heart Failure / Q000503:physiopathology*; D006439:Hemodynamics; D016591:Histocytological Preparation Techniques; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000737:chemistry / Q000378:metabolism; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000737:chemistry / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012433:Ryanodine / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D000697:Central Nervous System Stimulants; D011506:Proteins; D012433:Ryanodine; D002110:Caffeine; D002118:Calcium