Aminergic Receptors in Drosophila melanogaster: Responsiveness of Adenylate Cyclase to Putative Neurotransmitters

Abstract

Adenylate cyclase in Drosophila melanogaster heads is stimulated 5–6-fold by low concentrations of octopamine. The octopamine stimulation is inhibited by low concentrations of the α-adrenergic ligands phentolamine and dihydroergotamine and of chlorpromazine, but not by low concentrations of the β-antagonist propranolol and by the α-antagonist yohirnbine. d-Tubocurarine enhances the octopamine effect. Tyramine, norepinephrine, and epinephrine also stimulate the cyclase, probably via the octopamine receptor. Serotonin and dopamine stimulate Drosophila adenylate cyclase 1.3-1.4-fold; at least the latter putative neurotransmitter seems to interact with a receptor distinct from the octopamine receptor. Prolonged incubation with dopamine in vitro abolishes adenylate cyclase basal activity as well as responsiveness to guanyl nucleotides, NaF, and putative neurotransmitters.