Long-term culture and characterization of the adult ventricular and atrial cardiac muscle cell.

: Ventricular and atrial cardiac muscle cells isolated from the adult rat have been cultured and characterized. Once established in culture these myocytes resemble morphologically their in vivo counterparts except that they are flattened on the surface of the culture flask. These cultured cells possess differentiated ultrastructural characteristics including sarcomerically arranged myofilaments, appropriately organized sarcoplasmic reticulum, intercalated discs and a highly organized transverse tubular system. These cells regain the capacity to carry out semiconservative DNA replication; this capacity had previously been thought to have permanently been lost during early neonatal development. Other studies have shown that cultured ventricular myocytes resemble metabolically the in vivo and isolated perfused rat heart and that they possess an adenylate cyclase system which responds appropriately to adrenergic stimulation. These cells also appear electrophysiologically to resemble the intact adult heart. Long-term culture of adult cardiac muscle cells provides a new and unique system which can be used to study the structure and function of the adult mammalian ventricular and atrial cardiac myocyte.