Antennal lobe neurons of the honey bee, Apis mellifera, express a D2-like dopamine receptor in vitro.
We have used the D2-specific dopamine receptor ligand spiperone [N-(p-aminophenethyl) spiperone; NAPS] coupled to the fluorophore 7-nitrobenz-2-oxa-1,3-diazole-4-yl (NBD) to visualize dopamine receptors expressed in vitro by neurons of the primary antennosensory centers (antennal lobes) of the brain of the honey bee, Apis mellifera. Changes in the percentage of antennal lobe neurons exhibiting spiperone binding sites over time in culture and at different stages of metamorphic adult development have been investigated. Neurons obtained from animals at all stages of development exhibited spiperone binding sites, but only after 2 days or more in vitro. The percentage of antennal lobe neurons in vitro expressing spiperone binding sites increased significantly with the development of the antennal lobe neuropil. Fluorescently labelled spiperone (120 nM) could be displaced effectively by 1 mM dopamine but not by the same concentration of tyramine, octopamine, or serotonin. In addition, the D2 antagonist spiperone and the D2/D1 antagonist fluphenazine were more effective at displacing the fluorescent ligand than the D1-specific antagonist SCH23390. Our results indicate that Apis antennal lobe neurons in culture express a dopamine receptor and that this receptor is more likely to be D2-like than D1-like in nature. The receptor is expressed early in the metamorphic adult development of the antennal lobe neuropil of the brain.
Kirchhof
B S
BS
Centre for Neuroscience and Department of Zoology, University of Otago, Dunedin, New Zealand. barbara.kirchhof@stonebow.otago.ac.nz
Mercer
A R
AR
D000818:Animals; D001516:Bees / Q000502:physiology*; D001667:Binding, Competitive / Q000502:physiology; D002478:Cells, Cultured; D004298:Dopamine / Q000502:physiology; D018492:Dopamine Antagonists / Q000378:metabolism; D005456:Fluorescent Dyes; D008024:Ligands; D009474:Neurons / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000096:biosynthesis*; D012679:Sense Organs / Q000294:innervation* / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism
D018492:Dopamine Antagonists; D005456:Fluorescent Dyes; D008024:Ligands; D017448:Receptors, Dopamine D2; D013134:Spiperone; D004298:Dopamine