Repetitive firing and wing stiffness in the locomotory musculature of the pteropod Clione limacina

• Published in: Invertebrate Biology
• Main Author: Satterlie, Richard A.
• Other Authors: National Science Foundation, National Institutes of Health
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Clione limacina
• Online Access: http://dx.doi.org/10.1111/ivb.12233; https://onlinelibrary.wiley.com/doi/pdf/10.1111/ivb.12233; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/ivb.12233; https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/ivb.12233

Abstract The locomotory musculature of the pteropod Clione limacina includes slow‐twitch, fatigue‐resistant muscle fibers and fast‐twitch fatigable fibers. Dorsal musculature produces a dorsal bend of the wing, while ventral musculature produces a ventral bend. During the change to fast swimming, ~10% of the slow‐twitch fibers, including both dorsal and ventral fibers, exhibit fast repetitive firing that greatly exceeds the in‐phase excitation of the appropriate wing musculature. The normal wing‐beat frequency for fast swimming is 2–4 Hz, while repetitive firing occurs at 11 Hz. A component of fast‐swimming control is excitation of Pd‐ SW neurons of the pedal ganglion. These cells are serotonin immunoreactive, and they innervate the slow‐twitch musculature of the wing. Induced excitation of a Pd‐ SW neuron was capable of triggering repetitive firing in some slow‐twitch muscle cells. Repetitive firing in a subset of muscle fibers of the swim musculature could represent a contribution to wing stiffening, which has been documented to occur during the change to fast swimming.