The modulatory neurotransmitters that trigger biochemical cascades underlying olfactory learning in Drosophila mushroom bodies have remained unknown. To identify molecules that may perform this role, putative biogenic amine receptors were cloned using the polymerase chain reaction (PCR) and single-strand conformation polymorphism analysis. One new receptor, DAMB, was identified as a dopamine D1 receptor by sequence analysis and pharmacological characterization. In situ hybridization and immunohistochemical analyses revealed highly enriched expression of DAMB in mushroom bodies, in a pattern coincident with the rutabaga-encoded adenylyl cyclase. The spatial coexpression of DAMB and the cyclase, along with DAMB's capacity to mediate dopamine-induced increases in cAMP make this receptor an attractive candidate for initiating biochemical cascades underlying learning.