title: Increased sensitivity of ventricular myocardium to intracellular calcium-overload in Syrian cardiomyopathic hamster.
abstract: Papillary muscles of Syrian hamsters with morphologically defined cardiomyopathy (CM), and of control hamsters (Co) have been studied electrophysiologically. Co and CM muscles differ significantly in the following electrophysiological parameters: resting potential (-79.8 +/- 2.9 mV in Co, -74.3 +/- 5.5 mV in CM), action potential duration at 25% repolarization (30.0 +/- 3.6 ms in Co, 25.1 +/- 2.7 ms in CM), and at 90% repolarization (120.0 +/- 21.9 ms in Co, 171.6 +/- 24.1 ms in CM), upstroke velocity of phase 0 depolarization (73.7 +/- 12.8 V/s in Co, 48.4 +/- 8.7 V/s in CM). When superfused with K+-free solutions Co muscles did not show any oscillatory after-potentials up to 15 mmol/l CaCl2. In contrast to this CM muscles respond to K+-free superfusion with oscillatory afterpotentials, transient spontaneous activity and dramatically reduced upstroke velocity. CM muscles respond much more sensitively to an intracellular Ca2+ overload than Co preparations.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D009202:Cardiomyopathies / Q000503:physiopathology*; D006224:Cricetinae; D004195:Disease Models, Animal; D004558:Electric Stimulation; D005260:Female; D006352:Heart Ventricles / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D008647:Mesocricetus; D010210:Papillary Muscles / Q000187:drug effects / Q000473:pathology; D011188:Potassium / Q000494:pharmacology
chemical_list: D011188:Potassium; D002118:Calcium