CHARACTERIZATION OF A DOPAMINE D1 RECEPTOR FROM APIS-MELLIFERA - CLONING, FUNCTIONAL EXPRESSION, PHARMACOLOGY, AND MESSENGER-RNA LOCALIZATION IN THE BRAIN

The neurotransmitter dopamine is an important regulator of physiologic al and behavioral functions in both vertebrates and invertebrates. We have isolated a homologue of the vertebrate dopamine D1 receptor subfa mily from the honeybee Apis mellifera. [H-3]Lysergic acid diethylamide specifically binds to the heterologously expressed receptor with K-D similar to 5 nM. Dopaminergic receptor ligands compete for this high-a ffinity binding, with the following order of potency: R(+)-lisuride > chlorpromazine = cis(Z)-flupentixol > dopamine > S(+)-butaclamol > R()-SCH 23390 > haloperidol. Activation of the heterologously expressed receptor of Apis mellifera leads to cyclic AMP production. Receptor mR NA is expressed in perikarya of different brain neuropils, including t hose of mushroom body intrinsic neurons, These results suggest that th is dopamine receptor is involved in signal processing of visual and ol factory information in the honeybee, .