Motor systems I: Lower systems
Contractile properties of smooth muscle. A. Video image of an isolated gastric smooth muscle cell: (left) in normal Ringer's; (middle) 15 sec after pressure ejection of Ach from pipette tip at lower right; note vigorous contraction; (right) recovery after 4 min. B. Electrical response of another cell to the cholinergic agonist muscarine. The trace shows intracellular recording of slow burst of Ca2+ action potentials which generate the muscle contraction.