Résumé
In insects, circulation of haemolymph is driven by the auto rhythmic contraction of the dorsal heart vessel located in the abdomen. In a previous study, a recently authorized class of insecticides was found highly toxic when honey bees were exposed through the dorsal abdomen, suggesting cardiotoxic effects. In order to explore cardiotoxicity, enzymatically isolated heart cells were obtained from bees and their function was explored with traditional electrophysiological methods (current-clamp, voltage-clamp, intracellular microelectrode) and calcium imaging. After cell isolation, morphometric cell parameters measured under transmitted light microscopy were consistent with their in situ morphology observed in intact heart. Action potentials obtained under current-clamp with a patch pipette resembled AP recorded with intracellular electrodes in intact heart. Under voltage-clamp, ionic currents were recorded and their basic pharmacology could be defined. Confocal microscopy was used to assess calcium homeostasis. The honey bee intact cardiomyocytes preparation may help better understand insect heart excitability and insecticide cardiotoxicity.