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  • Author: M. Sabová x
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Abstract

Oxamyl is a carbamate insecticide used to control a broad spectrum of insects. It can also affect non-targeted organisms when applied incorrectly. The world food production depends partially on honeybee pollination abilities and therefore it is directly linked to the health of bees. The success of the colony development depends, among other factors, on the health of the larvae. The first 6 days are crucial for their development. In this stage, the worker larvae grow exponentially and may be exposed to xenobiotics via their diet. In this study, we investigated the effect of oxamyl on honeybee larvae (Apis mellifera) by monitoring the changes in their antioxidant enzyme system. The activities of superoxide dismutase, catalase and glutathione-S-transferase were determined in the homogenates of in vitro reared honeybee larvae after their single dietary exposure to oxamyl at doses of 1.25, 2.5, 5, 10 and 20 µg a.i./larva (a. i.—active ingredient). The doses of oxamyl did not cause statistically significant changes in the activities of the enzymes. Even a slight activation of these enzymes protected the larvae from the adverse effects of the reactive oxygen species (ROS). Marked changes in both the enzyme activity and the content of lipid peroxidation products were observed at the oxamyl dose of 10 µg a. i./larva. This fact may indicate a potential oxidative damage to the larvae. These results allowed us to assume that the toxic effects of oxamyl involves not only the inhibition of acetylcholine esterase but is also associated with ROS production.

Abstract

Methamphetamine is one of the most popular recreational drugs in Central Europe and is often combined with ethanol. Various interactions between these two substances have been described including the influence of administered ethanol on biotransformation of methamphetamine. The aim of the present study was to describe the opposite effect - the influence of methamphetamine on biotransformation of ethanol in rats. Methamphetamine was administered for 10 days (10 mg/kg/day) i.p. and ethanol was delivered as an intragastric bolus (2 g/kg) on the10th day of experiment to both methamphetamine administered rats and control animals. The pharmacokinetic experiment on the whole animal was performed and plasma samples were drawn at the 40th, 120th, 210th and 300th minute after ethanol administration. Ethanol plasmatic levels reached significantly lower values in the 40th and 120th interval when compared to controls. Differences were insignificant in the last two intervals. Our results suggest that chronic methamphetamine administration induces ethanol biotransformation. We suppose that this effect is caused by induction of alcohol dehydrogenase metabolic activity or by allosteric interaction of methamphetamine and this enzyme. More studies have to be conducted to confirm or disprove our hypothesis.