Avaliação da toxicidade induzida pelo organofosforado triclorfon em modelo experimental de insetos

Abstract

Triclorfon is an organophosphate that inhibits the acetylcholinesterase activity in both insects and mammals. The objective of this work was to study the toxicological effects induced by Trichlorfon in insects. We used cockroach and adult flies of the species Phoetallia palida and Drosophila melanogaster, respectively. Tests were conducted in vitro inhibition of acetylcholinesterase, determining the LD50, semi-isolated heart preparation, test grooming and test neurolocomotora activity. Statistical analysis was performed using the methods "t"Student test or ANOVA. Results were considered significant when p <0.05.Our data demonstrated that Triclorfon 50mM was the LD50 dose when assayed in Drosophila melanogaster. This dose is lesser than those described in the compound information and denotes that a super dosage has been applied by users improving the chance of intoxication. In our experimental conditions the Triclorfon induced alterations in the cardiac chronotropism. This effect was antagonized by atropine suggesting that not only the nerves assayed to the heart can regulate the frequency of beating but probably muscarinic receptors at Purkinge fibers must be involved. The effects on central and peripheral nervous system were also evidenced and demonstrated that in both systems there are acetylcholinesterase enzymes susceptible to the Triclorfon actions. In conclusion Triclorfon is an organophosphate insecticide that induced alterations in both cardiovascular and nervous systems of Phoetallia palida. These effects are associated to the acetylcholinesterase inhibition and demonstrated the presence of different cholinergic receptors involved in the cardiac frequency and also cholinergic receptors involved in the peripheral neurotransmission other than glutamatergic.