Study of serotonin interactions with brush border membrane of rabbit jejunum enterocytes.
Recent studies have demonstrated that serotonin (5-hydroxytryptamine, 5-HT) may interact with either specific receptors or with a specific transporter that takes up 5-HT in the gastrointestinal tract. The purpose of the present work was to study the 5-HT interactions with brush border membrane from rabbit jejunum enterocytes. The results obtained showed that 5-HT did not seem to be transported by any specific system of transport in brush border membrane vesicles. Nevertheless, [3H]5-HT seemed to bind specifically to this membrane. The kinetic analysis indicated a saturable and dissociable specific binding with a dissociation constant K(D)=14x10(-9) M. The saturation studies with [3H]5-HT indicated the presence of one specific site in the brush border membrane. The results of displacement of [3H]5-HT specific binding from the brush border membrane showed that both unlabelled 5-HT and unlabelled GR113080 ([1-[(2-methyl sulphonyl) amino] ethyl-4-piperidinyl] methyl-1-methyl-1H-indole-3-carboxylate), a specific competitive antagonist of 5-HT(4) receptors, inhibited the specific binding of [3H]5-HT to this membrane.
Alcalde
A I
AI
Department of Physiology, Veterinary Faculty, University of Zaragoza, Miguel Servet 177, 50013, Zaragoza, Spain. aacalde@psota.unizar.es
Sorribas
V
V
Rodriguez-Yoldi
M J
MJ
Lahuerta
A
A
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020895:Enterocytes / Q000166:cytology / Q000378:metabolism*; D004873:Ergolines / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007583:Jejunum / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000378:metabolism*; D017294:Ondansetron / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000378:metabolism* / Q000493:pharmacokinetics; D012702:Serotonin Antagonists / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D014316:Tritium
D004873:Ergolines; D007211:Indoles; D012702:Serotonin Antagonists; D013449:Sulfonamides; D014316:Tritium; D012701:Serotonin; D017294:Ondansetron; C032663:LY 53857; C082871:GR 113808