Premium
Photoaffinity Labeling of Adenylate Cyclase‐Linked Serotonin Receptors in Aplysia Neurons
Author(s) -
Saitoh T.,
Shih J. C.
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb01000.x
Subject(s) - cyclase , serotonin , adenylate kinase , piperazine , receptor , aplysia , 5 ht receptor , chemistry , biochemistry , medicine , endocrinology , biology , organic chemistry , neuroscience
Serotonin stimulated adenylate cyclase in Aplysia neurons with a K act of 0.7 μ M . Under the same conditions, 1 ‐[2‐(4‐aminophenyl)ethyl]4‐(3‐trifluoromethylphenyl)piperazine stimulated adenylate cyclase with a K act of 20 μ M . The azido derivative of this compound, 1‐[2‐(4‐azidophenyl)ethyl]4‐(3‐trifluoromethylphenyl)piperazine, or of serotonin, (4‐amino, 3‐nitrophenylazido‐serotonin), also stimulated the cyclase in the dark, but with lower efficiency ( K act < 10 −4 M ). Irradiation of the membranes in the presence of 100 μ M 1‐[2‐(4‐azidophenyl)ethyl]4‐(3‐trifluoromethylphenyl)piperazine abolished 75% of the cyclase activity stimulated by 5 μ M serotonin. Under the same conditions, 100 μ M 4‐amino, 3‐nitrophenylazido‐serotonin did not inhibit serotonin‐stimulated adenylate cyclase activity. When [ 3 H] 1 ‐[2‐(4‐azidophenyl)ethyl]4‐(3‐trifluoromethylphenyl)piperazine (20 μ M ) was irradiated with membranes for 5 min at 4°C, a dozen peptides were labeled, as revealed by a fluorogram of sodium dodecyl sulfate‐polyacrylamide gels. Among them, the labeling of five polypeptides (molecular weights of 45,000, 55,000, 63,000, 80,000, and 94,000) was protected by the presence of 0.2 m M serotonin during photolysis. These peptides may be related to serotonin receptors.