Intracellular recordings were obtained from the ectodermal cells of the gastrozooids of the siphonophore, Agalma sp. Stimulated gastrozooids undergo rapid longitudinal contractions that are immediately preceded by a series of action potentials which propagate throughout the epithelium. These rapid potentials arise from a much slower graded depolarization. Both potentials are abolished in low sodium solutions. Fast action potentials persist in the presence of manganese ions but both the slow potentials and contraction are abolished.
- © 1981 by Company of Biologists