Modulation of brain serotonin by benzyl butyl phthalate in Fundulus heteroclitus (mummichog)
Endocrine-disrupting chemicals have been known to alter important animal behaviors by modulating serotonin (5-hydroxytryptamine, 5-HT) and dopamine. F. heteroclitus (mummichog) brain serotonin and dopamine levels were quantified by enzyme-linked immunosorbent assay (ELISA) following a 28-day exposure regimen involving daily doses of either 0.1 mg l−1 benzyl butyl phthalate (BBP) dissolved in acetone or acetone alone (0.1 mg l−1). No differences in mean brain mass or total protein homogenate were induced by exposure to the acetone vehicle or BBP in acetone. The acetone vehicle had no effect on dopamine, serotonin, or tyrosine hydroxylase levels, but acetone did decrease tryptophan hydroxylase levels (p = 0.011). Exposure to BBP in acetone decreased dopamine (p = 0.024), increased serotonin (p < 0.001), reduced tryptophan hydroxylase as compared to the acetone vehicle alone (p < 0.001), and had no significant effect on tyrosine hydroxylase levels. This study is the first to report modulation of F. heteroclitus brain serotonin and its enzyme tryptophan hydroxylase following sub-lethal exposure to BBP in an acetone vehicle. In addition, modulation of brain dopamine in F. heteroclitus, sans simultaneous modulation of tyrosine hydroxylase, was also observed. These findings support the use of F. heteroclitus for assessing sub-lethal BBP exposure.
KeywordsEstuary Fundulus Plasticizers Serotonin Dopamine
We thank the College of Arts and Sciences and School of Health Sciences at Quinnipiac University for support of this research through Faculty Research Grants. We also thank our colleagues in the Departments of Biological Sciences and Chemistry & Physical Sciences at Quinnipiac University for their support in terms of time, talent and space to conduct and analyze these experiments. We acknowledge and are grateful for support from the CT Audubon Coastal Center (Milford, Connecticut) for providing unlimited access to the fish collection site, the Community Foundation for Greater New Haven’s Q-River Fund for providing support to complete the chemical testing of all water samples, and T. Folks from Rocky Mountain Diagnostics for his assistance with the ELISA kits.
This study was funded by an internal granting process supported by Quinnipiac University, College of Arts and Sciences (CAS Grant-in-Aid 2017-2018) awarded to Lisa A. E. Kaplan, Ph.D.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in this study involving animals were in accordance with the ethical standards of Quinnipiac University, where the studies were conducted, and approved by Quinnipiac University’s IACUC. The research did not involve human participants.
Informed consent was obtained from all individual participants, specifically authors, for whom identifying information is included in this article.
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