Isolation and characterization of single myocardial cells from the quail, Coturnix coturnix japonica.

1. The enzymatic cell isolation technique was applied to the bird heart resulting in myocytes of which 10-50% maintained their spindle-shaped morphology, excluded the vital dye, Evans blue and tolerated physiological concentration of Ca2+ ions. 2. The length of spindle-shaped myocytes was on average 289 +/- 7 microns, and the maximum width was 10.2 +/- 0.3 microns. The mean length of the sarcomeres was 2.18 +/- 0.03 microns. 3. In electron micrographs the fine structure of the spindle-shaped myocytes looked normal--regular sarcomeric organization with clear A and I bands, mitochondria with tightly located cristae and well-developed sarcoplasmic reticulum (SR). 4. Most (80%) of the spindle-shaped myocytes were quiescent in physiological calcium concentration and practically all of them could be induced to twitch by electric field stimulation. Some beat spontaneously showing mostly slowly-propagating (135 +/- 6 microns/sec at 20 degrees C) contraction waves, so-called phasic contractions. Sometimes spontaneous twitch-type contractions could also be seen.