Muscarinic receptor-mediated intracellular Ca2+ mobilization in embryonic chick heart cells

AbstractActivation of muscarinic receptors of heart cells elevates the intracellular Ca2+ concentration. The increase is considered to be due to influx of extracellular Ca2+. We show that intracellular Ca2+ mobilization is involved. Cell suspensions prepared from hearts of 6-day-old chick embryos were loaded with the fluorescent Ca2+ chelator chlortetracycline. Muscarinic stimulation induces a dose-dependent fluorescence decrease (ED50=2.6 × 10−6 M) indicating intracellular Ca2+ mobilization