title: Cytosolic [Ca2+], [Na+], and pH in guinea pig ventricular myocytes exposed to anoxia and reoxygenation.
abstract: The aim of this study was to evaluate whether the magnitude and time course of the intracellular acidification observed in anoxic cardiac myocytes was sufficient to protect against reoxygenation-induced hypercontracture. Cytosolic [Ca2+], [Na+], and pH were measured using fluorescent indicators in myocytes that were first subjected to both anoxia and glucose deprivation and then oxygen and glucose restoration 15-30 min after the onset of rigor. The cytosol underwent a profound acidification early in anoxia (pH 7.21 to 6.84) that reached a plateau at the time of rigor contracture. In contrast, [Na+] rose throughout anoxia. Cytosolic [Ca2+] underwent little rise during anoxia, but reoxygenation induced a large spike in [Ca2+]. Reoxygenation also induced a significant secondary acidification of the cytosol that was apparently induced by the spike in [Ca2+]. The characteristics of this secondary acidification were deemed sufficient to provide partial protection against the hypercontracture associated with the reoxygenation-induced [Ca2+] transient.
authors.affiliation: Department of Pharmacology, University of Kentucky College of Medicine, Lexington 40536-0084, USA.
authors.forename: L
authors.initials: L
authors.lastname: Ralenkotter
authors.forename: C
authors.initials: C
authors.lastname: Dales
authors.forename: T J
authors.initials: TJ
authors.lastname: Delcamp
authors.forename: R W
authors.initials: RW
authors.lastname: Hadley
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D006168:Guinea Pigs; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009994:Osmolar Concentration; D010100:Oxygen / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism*
chemical_list: D006859:Hydrogen; D012964:Sodium; D010100:Oxygen; D002118:Calcium