R4 PM Effects and Risk Assessment of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 4

(MCD-1117-650854) The impact of chronic, waterborne selective serotonin reuptake inhibitor (SSRI) exposure on toadfish physiology.

McDonald, M.D.¹, Julian, C¹, Riemer, D.D.¹, ¹ RSMAS, University of Miami, Miami, Florida, USA

ABSTRACT- Pharmaceuticals that modulate serotonin (5-hydroxytryptamine; 5-HT) are amongst the most prescribed in the United States. After consumption, selective serotonin reuptake inhibitors (SSRIs), which cause an increase in local 5-HT concentrations, are extensively metabolized by the liver. Their metabolites as well as 10-15% of the unchanged parent drug are eliminated from the body via the renal or gastrointestinal systems. Many consumed pharmaceutical compounds, including SSRIs, enter sewage treatment facilities and are not degraded. Consequently, these compounds have reached measurable quantities in surface waters. The potential contamination of the Florida Keys region and the Florida Keys National Marine Sanctuary (FKNMS) by these compounds is currently under investigation and the impact of pharmaceutical exposure on marine life in the area needs to be thoroughly examined. The gulf toadfish, Opsanus beta, is a benthic, marine teleost fish abundant along the Florida coastline and within the FKNMS. Recent work on the toadfish has shown that the HPI axis, branchial nitrogen excretion, branchial blood flow and intestinal ionoregulatory processes are regulated by 5-HT and both 5-HT receptors and transporters have been identified pharmacologically in these organs. To test the chronic impact of two of the most prescribed selective serotonin reuptake inhibitors (SSRIs) on gulf toadfish physiology, fish were separated into five waterborne exposure groups: control, 0.01 g/l fluoxetine-HCl (environmentally relevant), 10 g/l fluoxetine-HCl, 0.01 g/l sertraline-HCl or 10 g/l sertraline-HCl); and were exposed at these nominal concentrations for 60 days. The concentration of SSRIs in the water and accumulation in toadfish tissues and fluids were analyzed by liquid chromatography (LC)/ electrospray/ion trap mass spectrometry (MS) (Agilent Technologies and Bruker Daltronics) after appropriate sample extraction. The impact of chronic SSRI exposure on acid/base balance, the HPI axis, ionoregulation and 5-HT-regulated processes including branchial nitrogen excretion and branchial vascular resistance will be determined both in vivo and in vitro using a suite of physiological techniques.

Key words: fluoxetine, zoloft, anti-depressant, fish