title: Comparative study of [3H]ramosetron and [3H]granisetron binding in the cloned human 5-hydroxytryptamine3 receptors.
abstract: Characteristics of the binding of [3H]ramosetron to cloned human 5-hydroxytryptamine3 (5-HT3) receptors were investigated and directly compared to those of [3H]granisetron binding. Saturation studies revealed that [3H]ramosetron labeled more sites with high affinity (Kd=0.15+/-0.01 nM, Bmax =653 +/- 30 fmol/mg protein) than [3H]granisetron (Kd=1.17+/-0.25 nM, Bmax=427+/-43 fmol/mg protein). Kinetic studies revealed that dissociation of [3H]ramosetron was slower than that of [3H]granisetron. These results suggest that ramosetron is a highly potent 5-HT3-receptor antagonist.
authors.affiliation: Neuroscience Research, Pharmacology Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Akuzawa
authors.forename: H
authors.initials: H
authors.lastname: Ito
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism*; D001667:Binding, Competitive; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D017829:Granisetron / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014316:Tritium
chemical_list: D001562:Benzimidazoles; D017829:Granisetron; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D011993:Recombinant Fusion Proteins; D014316:Tritium; C071315:ramosetron