Behavioral effects of temperature sensitive mutations affecting metabolism of cAMP in Drosophila melanogaster

Temperature-sensitive mutations affecting metabolism of cAMP were obtained in Drosophila melanogaster to elucidate the possible involvement of cAMP in behavior. Temperature-dependent hypersensitivity to theophylline, propranolol and dihydroergotoxin following treatment with ethylmethanesulfonate was used to screen for such mutations in the X-chromosome. Biochemical analysis of cAMP content and activity of phosphodiesterase revealed two mutants with increased content of cAMP, 2 mutants with low activity of phosphodiesterase and 1 mutant with high activity of the enzyme. Locomotor activity of the ts-mutants correlated with cAMP content, increasing at 29 degrees C in mutants with an enlarged amount of cAMP and in mutants with low activity of phosphodiesterase and decreasing in the mutants with high activity of the enzyme. The latter mutant also failed to learn to avoid shock-associated odorant. One of the mutants with increased content of cAMP, but insensitive to propranolol, displayed better learning ability than the wild type. The learning performance of the mutants is interpreted proceeding from the metabolism of cyclic nucleotides in cholinergic and dopaminergic structures of the brain.