Effects of stress on brain acetylcholinesterase activity of a centipede Eupolybothrus nudicornis

With a view to using the centipede Eupolybothrus nudicornis as a bioindicator in biomonitoring programs we studied the effects of environmental pollution on the activity of the enzyme acetylcholinesterase (AChE) as neurotoxicity marker. Males and females were collected during the spring breeding season at two sites located in the eastern part of Algeria: Guelma (36°25’N, 7°25’E) and Annaba (36°52’ N, 7°45’ E). The Guelma site was considered as the healthy reference site as it was away from any source of pollution. On the other hand, the Annaba site was considered polluted due to the presence of an important steel complex. Individuals of both sexes from Annaba showed a lower brain AChE activity than those from Guelma which could probably be due to chemical pollutants from the steel complex. Moreover, as AChE is considered as an exposure biomarker of pesticides contamination, we tested the effect of a bisacylhydrazine ecdysteroid analog (RH-0345) used as insecticide on brain AChE activity of E. nudicornis. Brain AChE activity was determined 5, 10 and 15 days after injection of 10 µg of RH-0345. A significant decrease of brain AChE activity was observed in both males and females but the effect was much more pronounced in females.