PUBLICATION

Pharmacological modulation of the M-current shapes locomotor function in developing zebrafish

Authors
Gaudreau, S.F., Bui, T.V.
ID
ZDB-PUB-250507-4
Date
2025
Source
Journal of neurophysiology : (Journal)
Registered Authors
Keywords
M-current, escape response, locomotion, spinal circuits, zebrafish
MeSH Terms
none
PubMed
40327524 Full text @ J. Neurophysiol.
Abstract
The M-current (IM) is a non-inactivating potassium current that has been implicated in the control of locomotion in mammals, where it was shown to shape the rhythm governing locomotor movements. We tested whether IM might also be involved in the control of locomotor movements in developing zebrafish. Specifically, we investigated the involvement of IM in the execution of escape responses and swimming movement of zebrafish aged 4-5 days post-fertilization (dpf) using XE-991and ICA-069673, a pharmacological blocker and enhancer of IM, respectively. We found that IM may influence the number and type of swim bouts in an escape response but not the duration of the first bout nor the tail beat frequency. Enhancing IM reduced the distance swam with slow or fast swimming maneuvers by freely behaving larval zebrafish. We then studied whether IM is involved in locomotor output by spinal circuits using various approaches to induce motor activity in spinalized 4-5 dpf zebrafish. We found that while modulating IM during NMDA-evoked swimming activity had negligible effects, modulating IM during swimming activity evoked by a generalized depolarization of the spinal cord affected specific swimming parameters. In particular, XE-991 and ICA-069673 had opposite effects on overall spiking activity, swimming episode frequency and duration, and the number of bursts within each episode. In summary, IM was found to be involved in certain facets of escape response and swimming in larval zebrafish, and some of this influence resides within the expression of this current in spinal circuits.
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