Saitoh T, Shih J C
Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla.
J Neurochem. 1987 Nov;49(5):1361-6. doi: 10.1111/j.1471-4159.1987.tb01000.x.
Serotonin stimulated adenylate cyclase in Aplysia neurons with a Kact of 0.7 microM. Under the same conditions, 1-[2-(4-aminophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine stimulated adenylate cyclase with a Kact of 20 microM. 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 (Kact greater than 10(-4) M). Irradiation of the membranes in the presence of 100 microM 1-[2-(4-azidophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine abolished 75% of the cyclase activity stimulated by 5 microM serotonin. Under the same conditions, 100 microM 4-amino, 3-nitrophenylazido-serotonin did not inhibit serotonin-stimulated adenylate cyclase activity. When [3H]1-[2-(4-azidophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine (20 microM) was irradiated with membranes for 5 min at 4 degrees 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 mM serotonin during photolysis. These peptides may be related to serotonin receptors.
血清素刺激海兔神经元中的腺苷酸环化酶，其半激活常数（Kact）为0.7微摩尔。在相同条件下，1-[2-(4-氨基苯基)乙基]4-(3-三氟甲基苯基)哌嗪刺激腺苷酸环化酶的Kact为20微摩尔。该化合物的叠氮衍生物，即1-[2-(4-叠氮苯基)乙基]4-(3-三氟甲基苯基)哌嗪，或血清素的叠氮衍生物（4-氨基，3-硝基苯基叠氮-血清素），在黑暗中也能刺激环化酶，但效率较低（Kact大于10^(-4)摩尔）。在100微摩尔1-[2-(4-叠氮苯基)乙基]4-(3-三氟甲基苯基)哌嗪存在下对膜进行照射，可消除5微摩尔血清素刺激的75%的环化酶活性。在相同条件下，100微摩尔4-氨基，3-硝基苯基叠氮-血清素不抑制血清素刺激的腺苷酸环化酶活性。当[3H]1-[2-(4-叠氮苯基)乙基]4-(3-三氟甲基苯基)哌嗪（20微摩尔）与膜在4℃下照射5分钟时，如十二烷基硫酸钠-聚丙烯酰胺凝胶的荧光图谱所示，有十几种肽被标记。其中，在光解过程中，0.2毫摩尔血清素的存在可保护五种多肽（分子量分别为45000、55000、63000、80000和94000）的标记。这些肽可能与血清素受体有关。
