title: High affinity binding of azasetron hydrochloride to 5-hydroxytryptamine3 receptors in the small intestine of rats.
abstract: The binding affinity of azasetron hydrochloride (azasetron) for the 5-hydroxytryptamine3 (5-HT3) receptor in a tissue preparation of rat small intestine was investigated by using [3H]granisetron as a radioligand. Scatchard analysis of specific [3H]granisetron binding revealed a single population of saturable binding sites in the tissue preparation. At this site, azasetron was concentration-dependently competitive with [3H]granisetron, and it inhibited the specific [3H]granisetron binding with a Ki value of 0.33 nM. Azasetron has a high affinity for 5-HT3 receptor in the gastrointestinal organ, the very site of its antiemetic action against chemotherapy-induced emesis.
authors.affiliation: Research Laboratories, Yoshitomi Pharmaceutical Industries, Ltd., Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Katayama
authors.forename: K
authors.initials: K
authors.lastname: Asano
authors.forename: K
authors.initials: K
authors.lastname: Haga
authors.forename: T
authors.initials: T
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D000932:Antiemetics / Q000378:metabolism* / Q000627:therapeutic use; D001665:Binding Sites; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism* / Q000627:therapeutic use; D017829:Granisetron / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism*; D007553:Isotope Labeling; D008297:Male; D010078:Oxazines / Q000378:metabolism* / Q000627:therapeutic use; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D014316:Tritium; D014839:Vomiting / Q000188:drug therapy
chemical_list: D000932:Antiemetics; D019086:Bridged Bicyclo Compounds, Heterocyclic; D017829:Granisetron; D010078:Oxazines; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D014316:Tritium; C070671:azasetron