A DOPAMINE-SENSITIVE AND OCTOPAMINE-SENSITIVE ADENYLATE-CYCLASE IN THE NERVOUS-SYSTEM OF OCTOPUS-VULGARIS

1. Adenylate cyclase activity was assayed in the optic lobe of Octopus vulgaris. 2. 2. Both octopamine and dopamine stimulate the octopus adenylate cyclase, apparently by competing with the same receptor site. 3. 3. (±)-2-Amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene-HBr (6,7-ADTN) and a number of phenylethanolamine derivatives stimulate the octopus adenylate cyclase activity. 4. 4. The dopamine D-1 antagonists R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-HCl (SCH-23390) and (±)-7-bromo-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-HCl (SKF-83566) are unable to antagonize the effects of dopamine and octopamine, and similarly ineffective is the agonist (±)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol-HCl (SKF-38393). 5. 5. No detectable binding of labelled SCH-23390 occurs on membrane preparations from octopus optic lobe.