[Differential action of 7 beta-hydroxycholesterol on myocardial cells and fibroblasts. Obtaining primary cultures of pure myocardial cells].

Newborn rat myocardial cells, grown in primary cultures, beat synchronously. Addition of 7 beta-hydroxycholesterol, at a 2.5 microM concentration, impairs this synchrony and may even stop any contraction. The associated fibroblasts no longer adhere to the support, and can be washed away by fresh culture medium. This restores the synchronous beatings of the myocardial cells, the viability of which is then even improved while they grow in the absence of fibroblasts.