Effect of lambda-cyhalothrin on memory and movement in mice after transient incomplete cerebral ischemia.

Lambda-cyhalothrin (LCH) is a synthetic pyrethroid used as an insecticide. The aim of the study was to investigate the effect of LCH on memory, movement activity, and co-ordination in mice exposed to bilateral clamping of the carotid arteries (BCCA). On the first postsurgical day, the examined animals (BCCA/LCH) were injected with LCH i.p. and trained in the passive avoidance task 30 min. after the injection. Controls were: sham-operated animals (SHAM), with their carotids exposed but not occluded, animals subjected to BCCA (BCCA), and sham-operated mice injected with LCH (SHAM/ LCH). In the following experiments, memory retention, working spatial memory, movement activity, and co-ordination were examined. Neither memory nor movement co-ordination were impaired by BCCA or LCH. Exploratory locomotor activity was significantly reduced in the BCCA/LCH group (p < 0.01 vs SHAM). Spontaneous movement activity was significantly reduced in the BCCA/LCH group (p < 0.001 vs SHAM, p < 0.05 vs BCCA, p < 0.001 vs SHAM/LCH), as well as in the BCCA group (p < 0.01 vs SHAM). Exposure to LCH coexisting with BCCA decreased motor activity in the mice in 2 subsequent 30-min. periods of observation. BCCA itself decreased motor activity in the 31-60 min. of observation. These results show that BCCA combined with exposure to a subtoxic dose of LCH does not impair memory; however, they affect behaviour by reducing the horizontal movement activity in mice.