Intracellular calcium response to isoproterenol in cultured cardiac myocytes from rats and humans.
Richards-DE; Mathias-PI; Toraason-M
Toxicologist 1995 Mar; 15(1):125
A comparative investigation was conducted on the intracellular calcium ([Ca2+]i) response of neonatal-rat and fetal-human cardiac myocytes to isoproterenol. Neonatal-rat cardiac myocytes were cultured using an established overnight trypsin-digestion procedure. Fetal-human hearts, procured from the Anatomic Gift Foundation (Laurel, MD), were shipped overnight to this laboratory in a Krebs-bicarbonate buffer on wet ice. Upon arrival, hearts were minced and serially digested with collagenase in a Krebs-HEPES buffer. All cardiac myocytes were cultured on quartz cover glasses in M199 supplemented with 10% newborn calf serum. The yield of human myocytes per heart varied considerably and was well below that achieved from the rat heart. Both human, and rat cultures contained spontaneously beating: myocytes which were used for [Ca2+]i assessment 2-3 days (rat) or 4-5 days (human) after plating. [Ca2+]i was estimated Sopectrofluorometrical1y in myocytes loaded with fura-2. Basal [Ca2+]j levels and responses to high calcium (5 mM) or to isoproterenol (1 nM-10uM) were, in general, comparable between rat, and human cardiac myocytes. Specific differences were observed at peak systolic calcium, which averaged 420 nM in rat myocytes and 600 nM in human myocytes. Rat cardiac myocytes also tended to have a slightly higher sensitivity to isoproterenol than did human cardiac myocytes. Results demonstrate that cardiac myocytes obtained from fetal-human heart have the potential to be used routinely for experimental investigation. Results also demonstrate that the rat model is a good predictor of the human model, with respect to the variables examined here.
Animal-studies; Laboratory-animals; Myocardium; Heart; Humans; Cell-function; Cell-morphology
The Toxicologist. Society of Toxicology 34th Annual Meeting, March 5-9,1995, Baltimore, Maryland