Acetylcholine, GABA and glutamate induce ionic currents in cultured antennal lobe neurons of the honeybee, Apis mellifera.
The honeybee, Apis mellifera, is a valuable model system for the study of olfactory coding and its learning and memory capabilities. In order to understand the synaptic organisation of olfactory information processing, the transmitter receptors of the antennal lobe need to be characterized. Using whole-cell patch-clamp recordings, we analysed the ligand-gated ionic currents of antennal lobe neurons in primary cell culture. Pressure applications of acetylcholine (ACh), gamma-amino butyric acid (GABA) or glutamate induced rapidly activating ionic currents. The ACh-induced current flows through a cation-selective ionotropic receptor with a nicotinic profile. The ACh-induced current is partially blocked by alpha-bungarotoxin. Epibatidine and imidacloprid are partial agonists. Our data indicate the existence of an ionotropic GABA receptor which is permeable to chloride ions and sensitive to picrotoxin (PTX) and the insecticide fipronil. We also identified the existence of a chloride current activated by pressure applications of glutamate. The glutamate-induced current is sensitive to PTX. Thus, within the honeybee antennal lobe, an excitatory cholinergic transmitter system and two inhibitory networks that use GABA or glutamate as their neurotransmitter were identified.
Barbara
Guillaume Stephane
GS
Institut für Biologie, AG Neurobiologie, Freie Universität Berlin, Königin-Luise-Str. 28-30, 14195, Berlin, Germany.
Zube
Christina
C
Rybak
Jürgen
J
Gauthier
Monique
M
Grünewald
Bernd
B
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001516:Bees; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists; D018698:Glutamic Acid / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008959:Models, Neurological; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D009833:Olfactory Pathways / Q000166:cytology*; D018408:Patch-Clamp Techniques / Q000379:methods; D011679:Pupa; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018755:GABA Agonists; D018756:GABA Antagonists; D007473:Ion Channels; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D006632:Histamine; D000109:Acetylcholine; D004837:Epinephrine