Sex differences in β-N-Methylamino-L-alanine effects on zebrafish behavioral response.

The β-N-methylamino-L-alanine (BMAA) is a neurotoxin produced by cyanobacteria and diatoms and related by triggered neurodegeneration. The exposure to neurotoxins has also been reported by causing emotional and neuroendocrine effects and these effects may be sex-specific. However, the effects of BMAA on emotions and pain, as well as neuroendocrine modulations remain poorly understood. Here, we evaluate potential sex differences in zebrafish behavioral responses to BMAA acute exposure on their anxiety and pain phenotypical behavioral repertoire and their neuroendocrine (cortisol) effects. Overall, sex differences in behavioral responses of adult zebrafish to BMAA exposure were demonstrated, as female fish reacted to it more strongly than males by altering their behavioral phenotype in both the novel tank and writhing -like behavior tests. In addition, sex differences were demonstrated in relation to time response, as male increased the writhing-like behavioral responses immediately after injection of BMAA, while female only 24-h after injection, reinforcing the painful stimulus caused by BMAA. However, the exposure to BMAA elevated the whole-body cortisol levels in both male and female zebrafish. Collectively, these findings emphasize the growing importance of studying sex differences in zebrafish, including the evaluation of neurotoxins effects on emotions and pain in this aquatic experimental model.