Recent advances in the functional characterization of honeybee voltage-gated Ca2+ channels
Résumé
Voltage-gated Ca2+ (CaV) channels allow Ca2+ to enter the cell in response to membrane depolarization. This Ca2+ influx is not only necessary for cell excitability, but also triggers, via Ca2+-binding proteins, important biological functions such as contraction, synaptic transmission, or gene expression. Insect CaV channels are encoded by only three genes (against 10 in mammals), and their invalidation or pharmacological blockade is expected to have deleterious effects. They may thus constitute interesting targets for specific insecticides. However, the precise identification of the genes underlying the different Ca2+ currents recorded in different tissues, as well as the heterologous expression of these genes to screen selective molecules, have been proven to be difficult. This chapter reports on the recent successful expression of honeybee Ca2+ channels genes in Xenopus oocytes and reviews pharmacological properties of Ca2+ currents recorded in isolated honeybee neurons and muscle cells.