Efeito neurotóxico do extrato contendo anatoxina-a(s) em Nauphoeta cinerea: comparação com o organofosforado triclorfon

Abstract

Anthropogenic actions are responsible for the process of eutrophication in aquatic ecosystems, increasing the probability of the occurrence of potentially toxic cyanobacteria blooming. Anatoxin-a (s) is a neurotoxic cyanotoxin considered to be the only natural organophosphate because was inhibitory activity on the enzyme acetylcholinesterase (AChE). The aim of this work were to use Nauphoeta cinerea cockroaches as a biomarker for the determination of the effects of Anatoxin-a(s), comparing with the organophosphate Trichlorfon (Tn) in in vivo, in situ, ex vivo and in vitro. The results obtained showed that the extract containing Anatoxin-a(s) (ECATAS) inhibited the activity of AChE, whose effects were equivalent to those of Tn. In addition, ECATAS and Tn significantly decreased N. cinerea leg twitch tension as well as induced a negative chronotropic effect on the cardiovascular system of these insects. It was also possible to observe that the exploratory locomotory behavior and grooming activity underwent relevant changes with the administration of ECATAS and Tn, thereby affecting the behavior of the animals. Electrophysiological recordings of N. cinerea leg also demonstrated that ECATAS and Tn decreased the generation of spontaneous neural compound action potentials (PACNE). Hence, this work demonstrates that cockroaches can be used as biological model for the detection of the contamination by Anatoxin-a(s) as well as of other organophosphates, helping in the processes of decontamination and early determination of the anthropic effects.