The clonal cell line A10 was derived by B. … The clonal cell line A10 was derived by B. Kimes and B. Brandt from the thoracic aorta of DB1X embryonic rat and possesses many of the properties characteristic of smooth muscle cells. The cells produce spontaneous action potentials at the stationary phase of the growth cycle and exhibit an increase in activity of the enzymes myokinase and creatine phosphokinase. Growth Properties: adherent, A sample of a specimen consisting of a thin plane produced through the use of a microtome or other cutting device, usually produced for the purposes of histological processing and/or microscopic examination. processing and/or microscopic examination.