Noradrenaline stimulates 5-hydroxytryptamine release from mouse ileal tissues via alpha(2)-adrenoceptors.
The effect of noradrenaline on 5-hydroxytryptamine (5-HT) release from isolated mouse ileal tissues was investigated. Noradrenaline, but not isoprenaline, at 1 microM stimulated 5-HT release, an effect which was inhibited by yohimbine, an alpha(2)-adrenoceptor antagonist, but not by bunazosin, an alpha(1)-adrenoceptor antagonist. alpha(2)-Adrenoceptor agonists, UK 14,304 (5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline) and clonidine at a higher concentration (10 microM) also stimulated 5-HT release, while alpha(1)-adrenoceptor agonists, methoxamine and phenylephrine, had no effect. The effect of noradrenaline was completely abolished in ileal tissues isolated from mouse treated with pertussis toxin (100 microg/kg, i.v.) for 2 days. These results suggest that noradrenaline causes 5-HT release from enterochromaffin cells in mouse ileal tissues via alpha(2)-adrenoceptor subtypes coupled to a pertussis toxin-sensitive G protein.
Hirafuji
M
M
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. hirafuji@hoku-iryo-u.ac.jp
Ogawa
T
T
Kato
K
K
Hamaue
N
N
Endo
T
T
Parvez
H
H
Minami
M
M
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D000068438:Brimonidine Tartrate; D003000:Clonidine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D009638:Norepinephrine / Q000494:pharmacology*; D037342:Pertussis Toxin; D010656:Phenylephrine / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D011810:Quinoxalines; D018341:Receptors, Adrenergic, alpha-2; D010566:Virulence Factors, Bordetella; D010656:Phenylephrine; D015016:Yohimbine; D012701:Serotonin; D000068438:Brimonidine Tartrate; C018176:bunazosin; D037342:Pertussis Toxin; D008729:Methoxamine; D003000:Clonidine; D009638:Norepinephrine