title: Dextrose-, adenosine- and magnesium-induced protective actions during anoxia and reperfusion in canine Purkinje tissue.
abstract: 1. The effects of dextrose, magnesium (Mg) and adenosine on membrane potential and force of contraction were studied in driven and overdriven canine cardiac Purkinje tissue. 2. Dextrose (50 mmol/L) and adenosine (4-6 mmol/L) both showed protective action (the latter to a lesser extent) against simulated anoxia and reperfusion-induced arrhythmias, increased force of contraction transiently on reperfusion, and the former sustained the increase in force to a lower level as long as it was in the superfusing solution. 3. Dextrose (50 mmol/L) and Mg (5 mmol/L) restored overdrive-induced hyperpolarization during simulated anoxia. Adenosine was largely ineffective. 4. It was concluded that dextrose and adenosine (to a lesser extent) protect against arrhythmias by replenishing the critical intracellular pool of ATP which controls membrane transport of electrolytes such as K and Ca. Restoration of Na-K ATPase activity alone (as in the case of high Mg concentrations) is not sufficient to prevent arrhythmias.
authors: Department of Physiology, Meharry Medical College, Nashville, Tennessee.
authors: M L
authors: ML
authors: Bhattacharyya
authors: S
authors: S
authors: Sarker
authors: K
authors: K
authors: Seth
authors: B
authors: B
authors: Hughes
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000241:Adenosine / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D004285:Dogs; D005260:Female; D005947:Glucose / Q000494:pharmacology* / Q000627:therapeutic use; D000860:Hypoxia / Q000201:enzymology / Q000503:physiopathology*; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D015425:Myocardial Reperfusion; D011690:Purkinje Fibers / Q000187:drug effects* / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium; D005947:Glucose; D000241:Adenosine