The Role of Serotonin (5-HT) in Regulating the Hypoxic Hyperventilatory Response of Larval Zebrafish

FieldValue
dc.contributor.authorJensen, Gregory
dc.date.accessioned2016-09-21T18:35:30Z
dc.date.available2016-09-21T18:35:30Z
dc.date.issued2016
dc.identifier.urihttp://hdl.handle.net/10393/35196
dc.identifier.urihttp://dx.doi.org/10.20381/ruor-154
dc.description.abstractSerotonin (5-HT) containing neuroepithelial cells (NECs) are O2 sensitive chemoreceptors found throughout the skin of larval zebrafish (Danio rerio). Zebrafish larvae are sensitive to changes in ambient PO2 as early as 2 days post fertilisation (dpf) and hyperventilate in response to hypoxia beginning at 3 dpf. Tryptophan hydroxylase (tph) is the rate-limiting enzyme in 5-HT synthesis; three tph paralogs are present in zebrafish (tph1a, tph1b and tph2). Although 5-HT has been implicated as a key neurotransmitter mediating hypoxic hyperventilation, it has not been possible to discern the role of 5-HT specifically contained within the NECs in promoting hypoxic hyperventilation. The purpose of this study was to determine the role of NEC 5-HT in regulating the hypoxic ventilatory response in larval zebrafish. It was hypothesised that 5-HT is a key neurotransmitter released from NECs which contributes to hypoxic hyperventilation. Immunohistochemistry was used to determine the distribution of tph paralogs and their role in 5-HT production in NECs. Tph1a was present in NECs and nerves innervating NECs. Exposure to the non-selective tph inhibitor, para-chlorophenylalanine (pCPA), or translational gene knockdown of tph1a, diminished 5-HT expression within NECs. Exposure to acute hypoxia (PO2 = 30 mmHg) revealed a blunted hypoxic ventilatory response (reduced breathing frequency) in fish exhibiting depleted 5-HT in NECs. The hypoxic hyperventilatory response was rescued with application of 5-HT. The results of these experiments demonstrate that tph1a is responsible for 5-HT production in NECs of larval zebrafish, and that 5-HT released from NECs is involved in establishing their hypoxic hyperventilatory response.
dc.language.isoen
dc.publisherUniversité d'Ottawa / University of Ottawa
dc.subjecthypoxia
dc.subjectchemoreception
dc.subjectneuroepithelial cell
dc.subjecttryptophan hydroxylase
dc.titleThe Role of Serotonin (5-HT) in Regulating the Hypoxic Hyperventilatory Response of Larval Zebrafish
dc.typeThesis
dc.contributor.supervisorPerry, Steve
thesis.degree.nameMSc
thesis.degree.levelMasters
thesis.degree.disciplineSciences / Science
uottawa.departmentBiologie / Biology
CollectionThèses, 2011 - // Theses, 2011 -

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