SATTERLIE, RA; PIRTLE, TJ; Arizona State University; Arizona State University: Mechanisms of Swim Acceleration in the Pteropod Mollusc Clione limacina

The pteropod mollusk, Clione limacina, swims by rhythmic dorsal-ventral flexion of a pair of wing-like parapodia. Usually, Clione swim slowly and continuously upward to maintain a stable position in the water column. Variability in locomotor speed in Clione involves increases in cycle frequency, increases in the contractility of the wing musculature, and biomechanical changes in wing movements. A modulatory system of serotonergic cells in the cerebral ganglia of Clione has been shown to modulate swim activity to enhance swimming speed. Stimulation of the cerebral serotonergic cells or bath application of serotonin has several effects on the swim interneurons comprising the Clione swim central pattern generator to increase the cycle frequency of swim activity. These include a baseline depolarization, a decrease the spike duration, enhancement of postinhibitory rebound amplitude, and a decrease in the latency to peak postinhibitory rebound.