Role of Ca2+ in membrane excitation and cell motility in Characean cells as a model system.

摘要: Abstract The Characeae internodal cell is excitable and generates an action potential. depolarizing phase of the potential primarily reflects activation Cl − channels, which takes place in a Ca 2+ -dependent manner. Namely, increase influx at very beginning heightens concentration cytoplasm ([Ca ] c ). high [Ca activates channels plasmalemma, resulting large depolarization. also acts as signal to induce tonoplast instantaneous cessation cytoplasmic streaming; caused by -induced tonoplast, result inhibition actin-myosin interaction . When cell, especially Nitella flexilis , hydrated rapidly, increases through release from intracellular store(s). may be triggered stretchingof endomembranes osmotic swelling store lumens. Although origin different that case potential, not only induces membrane depolarization channel manner but inhibits streaming Characeae.