Stimulation by Dopamine of Adenylate Cyclase in Retinal Homogenates and of Adenosine-3′:5′-Cyclic Monophosphate Formation in Intact Retina

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 69; no. 3; pp. 539 - 543
• Main Authors: Brown, Joan Heller, Makman, Maynard H.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.03.1972; National Acad Sciences
• Subjects: Adenylyl Cyclases - analysis; Adenylyl Cyclases - metabolism; Adrenergics; Animals; Biological Sciences: Biochemistry; Brain; Catecholamines; Cattle; Cyclic AMP - analysis; Cyclic AMP - biosynthesis; Dopamine - pharmacology; Enzyme Activation; Enzymes; Epinephrine - pharmacology; Hormones; In Vitro Techniques; Isoproterenol - pharmacology; Male; Norepinephrine; Norepinephrine - pharmacology; Ouabain - pharmacology; Phenoxybenzamine - pharmacology; Phentolamine - pharmacology; Phosphotransferases - analysis; Propranolol - pharmacology; Proteins; Rats; Receptors; Retina; Retina - analysis; Retina - enzymology; Retina - metabolism; Ungulates
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.69.3.539

A catecholamine-sensitive adenylate cyclase system is present in homogenates of both calf and rat retinas. Dopamine is a more potent activator of the bovine enzyme than is norepinephrine or epinephrine. Cyclic AMP concentrations in intact bovine retina are increased by dopamine, as well as by other catecholamines, and by depolarizing agents. Studies with adrenergic blocking agents suggest that the stimulation of retinal adenylate cyclase by catecholamines cannot be clearly defined in terms of the characteristics of alpha or beta adrenergic receptors. Bovine retina also contains a protein kinase that is stimulated 20-fold by cyclic AMP. It is proposed that dopamine is the major activator of a retinal adenylate cyclase, and that this activation is related to its role as a neurotransmitter.