Correlation of changes in cardiac calcium channels with hemodynamics in Syrian hamster cardiomyopathy and heart failure.
We compared hemodynamics with [3H]nitrendipine (calcium channel) binding to cardiac membranes from Bio 14.6 cardiomyopathic Syrian hamsters at 4 and 10 months with their F1B controls. A 50% increase in the number (Bmax) of nitrendipine binding sites (calcium channels) was seen only in the 4 month old myopathic vs controls (Bmax = 468 +/- 11 vs 309 +/- 10 fmol/mg prot with no change in affinity (KD) (KD = .65 +/- .12 vs .75 +/- .14 nM), while no differences in Bmax or KD were seen at 10 months (Bmax = 375 +/- 9 vs 362 +/- 7 fmol/mg prot/KD = .82 +/- .18 vs .89 +/- .17 nM) myopathic vs control respectively. Hemodynamic studies revealed no significant differences in cardiac output, cardiac index, stroke volume, heart rate, mean arterial pressure, peripheral resistance, body weight, heart weight at 4 months, but a significant decrease in peripheral resistance (1120 +/- 360 vs 2080 +/- 240) increase in body weight (118 +/- 2 vs 94 +/- 2 grams) and heart weight (97 +/- 5 vs 78 +/- 2 gms/100 gms body weight) in 10 month myopathic vs control animals. We conclude that the onset of cardiomyopathy at 4 months is associated with a selective increase in calcium channel binding sites and heart failure at 10 months is associated with a relative decrease in these sites.
D000818:Animals; D001835:Body Weight; D002118:Calcium / Q000378:metabolism*; D009202:Cardiomyopathies / Q000503:physiopathology*; D006224:Cricetinae; D006333:Heart Failure / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D007473:Ion Channels / Q000378:metabolism*; D008647:Mesocricetus; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009568:Nitrendipine / Q000378:metabolism; D009929:Organ Size; D014655:Vascular Resistance
D007473:Ion Channels; D009568:Nitrendipine; D002118:Calcium