title: 5-HT receptor subtypes involved in the serotonin-induced inhibition of L-leucine absorption in rabbit jejunum.
abstract: The aim of the present study was to determine the 5-HT receptor subtypes involved in the serotonin-induced inhibition of L-leucine absorption across rabbit jejunum in vitro. A number of agonists and antagonists were used to characterize the receptors through which serotonin inhibits this absorption. The results show that 2.5x10(-6) M 5-HT inhibits the amino acid absorption by about 20%. The 5-HT receptor agonists, alpha-methyl-5-HT (5-HT2), 2-methyl-5-HT (5-HT3) and zacopride (5-HT4) at concentrations 2.5x10(-6) and 2.5x10(-5) M produced 10-30% inhibition on L-leucine intestinal absorption. 5-carboxyamidotryptamine (5-HT1) did not produce any inhibition. The 5-HT antagonists, GR 113808A (5-HT4) at 2.5x10(-6) M and ritanserin (5-HT2) and ondansetron (5-HT3) at 2.5x10(-5) M completely blocked the effect of 5-HT. However, methiothepin (5-HT1) did not produce any effect on serotonin action in the intestinal absorption of amino acid. It can be concluded that 5-HT2, 5-HT3 and 5-HT4 receptors could mediate inhibition of L-leucine absorption across rabbit jejunum.
authors.affiliation: Departamento de Fisiología, Facultad de Veterinaria, Zaragoza, Spain.
authors.forename: M T
authors.initials: MT
authors.lastname: Salvador
authors.forename: M C
authors.initials: MC
authors.lastname: Rodríguez-Yoldi
authors.forename: A I
authors.initials: AI
authors.lastname: Alcalde
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodríguez-Yoldi
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000378:metabolism; D007930:Leucine / Q000378:metabolism*; D008297:Male; D017294:Ondansetron / Q000494:pharmacology; D011817:Rabbits; D011985:Receptors, Serotonin / Q000502:physiology*; D044406:Receptors, Serotonin, 5-HT3; D044422:Receptors, Serotonin, 5-HT4; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D001549:Benzamides; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007211:Indoles; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D013449:Sulfonamides; D016713:Ritanserin; D044422:Receptors, Serotonin, 5-HT4; C042390:alpha-methylserotonin; D012701:Serotonin; D017294:Ondansetron; C045918:2-methyl-5-HT; C055971:zacopride; D007930:Leucine; C082871:GR 113808