Behavioral alterations induced by repeated saxitoxin exposure in drinking water

 

Felipe Diehl^1 3, Patricia Baptista Ramos¹, Juliane Marques dos Santos¹, Daniela Martí Barros², João Sarkis Yunes¹

 

1 Postgraduate Program in Physical, Chemical and Geological Oceanography, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, RS, Brazil.

2 Postgraduate Program in Compared Animal Physiology, Institute of Biological Sciences, Federal University of Rio Grande (FURG), Rio Grande, RS, Brazil.

3 Institute of Oceanography, Federal University of Rio Grande (FURG), Caixa Postal 474, Rio Grande, RS CEP 96203-900, Brazil.

 

ABSTRACT

Background

Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats.

Methods

The effects of saxitoxin (3 or 9 μg/L STX equivalents) or cyanobacteria on behavior was determined using the open field habituation task, elevated plus maze anxiety model task, inhibitory avoidance task, and referential Morris water maze task.

Results

No effects of saxitoxin consumption was observed on anxiety and motor exploratory parameters in the elevated plus maze and open field habituation tasks, respectively. However, groups treated with 9 μg/L STX equivalents displayed a decreased memory performance in the inhibitory avoidance and Morris water maze tasks.

Conclusions

These results suggest an amnesic effect of saxitoxin on aversive and spatial memories.

 

Key words: Saxitoxin; Drinking water; Behavior; Aversive memory; Spatial memory; Rats

 

Funding

This research was supported by fellowships and grants from the Coordination for the Improvement of Higher Education Personnel (CAPES – PRODOC) and the National Council for Scientific and Technological Development (CNPq – MCT). JSY and DMB are research fellows of CNPq.

 

Received: December 2, 2015.

Revised: May 9, 2016.

Accepted: May 17, 2016.

 

Correspondence: felipedhl@gmail.com

 

Competing interests

The authors declare that they have no competing interests.

 

Authors’ contributions

FD wrote the first draft of the manuscript and revised it; he also performed all behavioral experiments. PBR contributed to experimental design and animal maintenance. JMS performed all chromatographic analysis. DMB and JSY helped in designing all the experiments and corrected the final version of article. All authors read and approved the final manuscript.

 

doi: 10.1186/s40409-016-0072-9