title: Calcium content of peripheral and central mitochondria in the guinea pig myocardium: electron probe analysis.
abstract: We quantitated subcellular elemental concentrations in stimulated and resting guinea pig myocardium to determine whether species-specific properties of guinea pigs or the subcellular localization of mitochondria accounted for reports of higher mitochondrial Ca in guinea pigs than in other species. Small papillary muscles or trabeculae isolated from guinea pig ventricles were stimulated to raise cytosolic [Ca(2+)](i) by two methods: (1). tetanizing by rapid pacing preparations in which Ca(2+) uptake by the sarcoplasmic reticulum was inhibited with cyclopiazonic acid or (2). freeze trapping paced muscles near-peak systole. Electron probe X-ray microanalysis showed no significant difference between the (low, approximately 0.4 mmol/kg dry weight) mitochondrial Ca content of stimulated guinea pig hearts, compared to mitochondria of other species, such as rat and hamsters, and the Ca contents of peripheral and central mitochondria were also not significantly different.
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, PO Box 800736, Jordan Hall 4-7, Charlottesville, VA 22908-0736, USA.
authors.forename: Ruoya
authors.initials: R
authors.lastname: Ho
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Fan
authors.forename: Avril V
authors.initials: AV
authors.lastname: Somlyo
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Somlyo
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002451:Cell Compartmentation / Q000187:drug effects / Q000502:physiology; D004577:Electron Probe Microanalysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009924:Organ Culture Techniques; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D013045:Species Specificity; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D002118:Calcium; C000543:cyclopiazonic acid