Figure 4.

Sequential induction of mRNA for c-fos, NRF-1, and Cyt c after electrical stimulation. RNA was isolated from neonatal rat cardiac myocytes cultured in serum-free medium either in the absence or presence of electrical stimulation. Northern blots for c-fos and Cyt c mRNA were quantified by densitometric scanning. Quantitation of NRF-1 expression was carried out using densitometric scanning with normalization to 18s RNA following generation of the riboprobe and separation of the RNA/RNA hybrids. “C” and “S” represent results from control, nonstimulated myocytes and from electrically stimulated myocytes. The results are representative of RNA isolated from three different cultures. RNA loading controls for each time point are summarized in Fig. 2.