Publication Date

2018-07-11

Availability

Embargoed

Embargo Period

2020-07-10

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Marine Biology and Ecology (Marine)

Date of Defense

2018-07-02

First Committee Member

M. Danielle McDonald

Second Committee Member

Marjorie F. Oleksiak

Third Committee Member

Lynne A. Fieber

Fourth Committee Member

Martin Grosell

Fifth Committee Member

William K. Milsom

Abstract

Serotonin, or 5-hydroxytryptamine (5-HT), is a powerful neurochemical with diverse physiological effects in vertebrates. In mammals, peripheral 5-HT is tightly regulated by uptake through the 5-HT transporter (SERT) into a circulating platelet storage pool. Teleost fish possess SERT but do not appear to have a similar circulating 5-HT storage pool; thus, this dissertation sought to elucidate alternate mechanisms of 5-HT control in the periphery of a model teleost, the Gulf toadfish (Opsanus beta). Toadfish SERT was first sequenced and characterized, revealing high conservation with other teleost SERTs, a ubiquitous distribution of transcript—with particularly high levels of transcript in the heart—and dose-dependent increases in plasma 5-HT upon SERT inhibition with fluoxetine (FLX), the active ingredient in Prozac and an aquatic pollutant. Acute FLX also reduced the ability of this hypoxia-tolerant fish to regulate its metabolic rate during hypoxia, although waterborne exposure to environmentally relevant levels did not. Further experiments examined the uptake of 5-HT into the heart and gill and the excretion pathways of 5-HT under normal physiological conditions and during hypoxia. Overall, this dissertation provides a comprehensive analysis of 5-HT handling in the periphery of the Gulf toadfish.

Keywords

5-hydroxytryptamine; 5-HT; SSRI; fluoxetine; hypoxia; uptake

Available for download on Friday, July 10, 2020

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