Related Experiment Video
Updated: May 16, 2026
08:01
Induction of Hypoxia in Living Frog and Zebrafish Embryos
Published on: June 26, 2017
Serotonergic and cholinergic elements of the hypoxic ventilatory response in developing zebrafish
Kamila Shakarchi1, Peter C Zachar, Michael G Jonz
1Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
The Journal of Experimental Biology
|November 17, 2012
Summary
Zebrafish gill neuroepithelial cells use serotonin and acetylcholine to sense oxygen levels, with these pathways developing at different times to manage breathing responses to hypoxia.
Area of Science:
- Comparative physiology
- Neurobiology
- Developmental biology
Background:
- Gill neuroepithelial cells (NECs) mediate fish hyperventilation to hypoxia, but chemosensory roles are unclear.
- Serotonin (5-HT) dominates O(2)-sensitive gill NECs in fish, unlike acetylcholine (ACh) in terrestrial vertebrates.
Purpose of the Study:
- Characterize developmental timing of gill serotonergic and cholinergic pathways in zebrafish.
- Investigate the roles of 5-HT and ACh in hypoxic ventilatory responses.
Main Methods:
- Immunolabeling of zebrafish gills at various developmental stages.
- In vivo administration of neurotransmitters and antagonists.
- Assessment of ventilation frequency (f(V)) changes.
- Identification of vesicular acetylcholine transporter (VAChT) positive cells.
Main Results:
- Serotonergic NECs present early; hypoxia reduced their numbers at 7 days post-fertilization (d.p.f.).
- 5-HT increased f(V) in early and late larvae; ACh increased f(V) only in late larvae.
- Ketanserin blocked hypoxia response at 10 d.p.f., hexamethonium at 12 d.p.f.; VAChT cells appeared by 14 d.p.f.
Conclusions:
- Zebrafish gill serotonergic and cholinergic pathways develop differentially.
- These distinct pathways contribute to the developmental regulation of hypoxic hyperventilation.
