We investigated here the role of transmissions mediated by GABA and glutamate-gated chloride channels (GluCls) in olfactory
learning and memory in honeybees, both of these channels being a target for fipronil. To do so, we combined olfactory conditioning
with injections of either the GABA- and glutamate-interfering fipronil alone, or in combination with the blocker of glutamate
transporter
l-
trans-Pyrrolidine-2,4-Dicarboxylicacid (
l
-trans-PDC), or the GABA analog
Trans-4-Aminocrotonic Acid (TACA). Our results show that a low dose of fipronil (0.1 ng/bee) impaired olfactory memory, while a
higher dose (0.5 ng/bee) had no effect. The detrimental effect induced by the low dose of fipronil was rescued by the coinjection
of
l-
trans-PDC but was rather increased by the coinjection of TACA. Moreover, using whole-cell patch-clamp recordings, we observed that
l-
trans-PDC reduced glutamate-induced chloride currents in antennal lobe cells. We interpret these results as reflecting the involvement
of both GluCl and GABA receptors in the impairment of olfactory memory induced by fipronil.
Keywords Honeybee - Olfactory memory - Patch-clamp - Fipronil - GluCl - GABA
Abdessalam Kacimi El Hassani and Julien Pierre Dupuis contributed equally to this work.