Influence du lindane sur le métabolisme respiratoire d'Asellus aquaticus L. Relation concentration — perturbation

Abstract

The respiratory metabolism of Asellus aquaticus L. was investigated after short-term exposure to lindane poisoning at 15 °C. After 48 h, oxygen consumption was individually recorded with a polarographic method using a Clark electrode and a Copenhagen radiometer.

The average oxygen consumption by poisoned individuals is higher than controls at concentrations lower than 8 µg·1⁻¹ but decreases to become lower than controls at higher dosages. If the metabolism of individuals is expressed as a function of weight, we find no significant correlation between weight and metabolism of poisoned Asellus, as opposed to controls. This result can be explained by the fact that poisoning intensity decreases with body weight at a given insecticide concentration, whereas metabolism increases as a function of weight. As a consequence there is apparently a lack of correlation between weight and metabolism amongst poisoned Asellus at dosages higher than 2 µg·1⁻¹. However, if metabolism is expressed as a metabolic ratio, a good correlation is observed between metabolism and weight of poisoned Asellus, the metabolic perturbation being significant at 4 µg·1⁻¹ and higher concentrations.

These results prompt us to conclude that, during the initial step of intoxication, an increase of the oxygen consumption occurs under weak poisoning conditions, while higher concentrations of insecticide give rise to a decrease in metabolism.