Unravelling impacts of the insecticide deltamethrin on neuronal sodium channels in honey bees: molecular insights and behavioural outcomes.

Fiche publication

Date publication

novembre 2024

Journal

Chemosphere

Auteurs

Membres identifiés du Cancéropôle Est :
Dr MUTTERER Jérôme

Tous les auteurs :
Kadala A, Kaabeche M, Charreton M, Mutterer J, Pélissier M, Cens T, Rousset M, Chahine M, Charnet P, Collet C

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/39617325

Résumé

The current risk assessment framework for insecticides suffers from certain shortcomings in adequately addressing the effects of low doses on off-target species. To remedy this gap, a combination of behavioural assays and in vitro cellular approaches are required to refine the precision of toxicity assessment. The domestic honey bee has long been standing as an emblematic pollinator in ecotoxicology, and once more, it provides us with a practical testing model for this purpose. First, newborn bees (D1) were found more vulnerable than 6 days-old bees (D6) to deltamethrin, a widely used α-cyano-3-phenoxybenzyle pyrethroid. In D1 bees, the range of doses inducing mortality was shifted towards lower values (∼2-fold) with a correspondingly lower LD (11 ng/bee). Moreover, at low doses that do not induce mortality in laboratory conditions, the locomotor behaviour of D1 bees was more impacted than in D6 bees. This was evidenced by an increase in immobility time and a decrease in locomotor performance across all tested doses for D1 bees (0.75, 1.5 and 3 ng/bee) during an automated 21 hours-long observations. Behavioural disorders are linked to deltamethrin's disruption of voltage-gated sodium channels (Nas) functions, as quantified in cultured neuronal cells. In the presence of deltamethrin, patch-clamp experiments revealed a concentration- and use-dependent slowing of Na kinetics. Channel's deactivation is slowed by three orders of magnitude at 10 μM deltamethrin. Two additional phenoxybenzyl pyrethroids, including the commonly used cypermethrin, elicited quantitatively similar effects on Na kinetics. The integration of in vitro cellular assays and behavioural assays may facilitate a deeper understanding and prediction of insecticides toxicity.