Abstract
Ctenophores are transparent marine organisms that swim by means of beating cilia; they are the simplest animals with individual muscle fibres. Predatory species, such as Beroe ovata, have particularly well-developed muscles and are capable of an elaborate feeding response1. When Beroe contacts its prey, the mouth opens, the body shortens, the pharynx expands, the prey is engulfed and the lips then close tightly. How this sequence, which lasts 1 s, is accomplished is unclear. The muscles concerned are structurally uniform2,3 and are innervated at each end by a neuronal nerve net4 with no centre for coordination. Isolated muscle cells studied under voltage-clamp provide a solution to this puzzle. We find that different groups of muscle cells have different time-dependent membrane currents. Because muscle contraction depends upon calcium entry during each action potential, these different currents produce different patterns of contraction. We conclude that in a simple animal such as a ctenophore, a sophisticated set of mem-brane conductances can compensate for the absence of an elaborate system of effectors.
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Bilbaut, A., Nicaise, ML., Leech, C. et al. Membrane currents that govern smooth muscle contraction in a ctenophore. Nature 331, 533–535 (1988). https://doi.org/10.1038/331533a0
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DOI: https://doi.org/10.1038/331533a0
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