title: The effect of halothane on the sarcoplasmic reticulum in normal and right ventricular hypertrophy in rabbits.
abstract: Calcium accumulation and storage by the sarcoplasmic reticulum is affected adversely by both inhaled anesthetics and hypertrophy. The interaction of these two conditions in right ventricular muscle was examined in a skinned fiber preparation whereby the sarcolemma was disrupted mechanically to permit external control of the chemical composition of the cytoplasm. Skinned fibers were obtained from the right ventricles of rabbits 4 mo after surgical banding of the pulmonary artery (n = 5) or sham banding (n = 4). Right ventricles after pulmonary artery banding weighed an average of twice that of normal right ventricles. The sarcoplasmic reticulum of the skinned fibers was permitted to accumulate Ca2+ and then maximal or submaximal Ca2+ release was induced with 25 mM or 2 mM caffeine, respectively. The magnitude of the Ca2+ release was estimated by the area of the ensuing tension over time. When 1%, 2%, or 3% halothane accompanied the 2 mM caffeine, both normal and hypertrophied muscle exhibited an area of the tension transient twice that of the tension transients without halothane (control). When present during Ca2+ accumulation, 1%, 2%, and 3% halothane reduced the 25 mM caffeine-induced tension transient in normal and hypertrophied muscle to 36%, 17%, and 11%, respectively, of the controls. The equal depression in normal and hypertrophied right ventricles was in contrast to a previous study in which hypertrophy provided some protection against the decrease in sarcoplasmic reticulum Ca2+ storage by halothane.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, University of Washington School of Medicine, Seattle.
authors.forename: G A
authors.initials: GA
authors.lastname: Rooke
authors.forename: J Y
authors.initials: JY
authors.lastname: Su
mesh_terms: D000769:Anesthesia, Inhalation; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006221:Halothane / Q000494:pharmacology*; D017380:Hypertrophy, Right Ventricular / Q000503:physiopathology*; D008297:Male; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D016278:Ventricular Function, Right / Q000187:drug effects* / Q000502:physiology
chemical_list: D002118:Calcium; D006221:Halothane