title: Electrophysiological study of Syrian hamster hereditary cardiomyopathy.
abstract: This study was performed to determine if the intracellular electrical activity of adult cardiac papillary muscle from a strain of Syrian hamster (B10 14.6) with a genetically determined cardiomyopathy was different from that of a control strain (B10 RB). Muscles driven at rates from 1 Hz through the physiological range. Resting potentials of muscle from the two strains were not significantly different, except in increased [C2+]0, where the control was slightly hyperpolarised. Action potential overshoot was significantly greater in the myopathic at all frequencies, while the upstroke velocity was not significantly different, except at 8 Hz where the myopathic value was depressed. Action potential durations at 20, 50 and 95% repolarisation were significantly greater in the myopathic, at all rates and with increased [C2+]0. Response of the muscles to verapamil and D600 were complex, with a decrease seen in duration at 20% repolarisation and an increase in 50% duration at 1 Hz rate. No strain-related difference in sensitivity to the drugs was seen. The results supporty the hypothesis that a sarcolemmal defect is intimately related to the genesis of the cardiomyopathy.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D009202:Cardiomyopathies / Q000235:genetics / Q000503:physiopathology*; D006224:Cricetinae; D005711:Gallopamil / Q000494:pharmacology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008647:Mesocricetus; D010210:Papillary Muscles / Q000187:drug effects / Q000503:physiopathology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D005711:Gallopamil; D014700:Verapamil