Figure 3.
Quantitation of ET-mediated conversion of embryonic ventricular myocytes into Purkinje fibers. (a) Dose dependency of response to ET in micromass cultures of E5 myocytes. (b) Induction of Purkinje fiber cells after 5 days exposure to ET, big-ET, basic fibroblast growth factor, and platelet-derived growth factor 10−7 M in monolayer cultures of E3 myocytes. (c) Neutralization of ET-mediated (at 10−8 M) conversion of E3 myocytes in micromass culture by BQ123 (at 10−5 M) and BQ788 (at 10−5M). (d) Age-dependency of conversion after 48-hr exposure to media containing ET (10−8 M) in micromass cultures of embryonic myocytes. Purkinje fiber (Pf)/M and bars indicate means and standard errors of sMHC+ cells within MF20-positive cells, respectively.