1. [Signal transduction of serotonin release from enterochromaffin cells in mouse ileal crypts].
- Author
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Hirafuji M, Kato K, Suzuguchi T, Ogawa T, Endo T, Satoh Y, and Minami M
- Subjects
- 4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone pharmacology, 8-Bromo Cyclic Adenosine Monophosphate pharmacology, Adrenergic alpha-Agonists pharmacology, Adrenergic alpha-Antagonists pharmacology, Animals, Brimonidine Tartrate, Calcium physiology, Clonidine pharmacology, Enterochromaffin Cells metabolism, In Vitro Techniques, Male, Mice, Mice, Inbred ICR, Norepinephrine pharmacology, Phosphodiesterase Inhibitors pharmacology, Prazosin pharmacology, Pyrrolidinones pharmacology, Quinazolines pharmacology, Quinoxalines pharmacology, Receptors, Adrenergic, alpha physiology, Receptors, Adrenergic, beta physiology, Rolipram, Yohimbine pharmacology, Enterochromaffin Cells physiology, Ileum metabolism, Serotonin metabolism, Signal Transduction physiology
- Abstract
Although serotonin (5-HT) release from enterochromaffin (EC) cells is considered to be regulated by multiple receptor-mediated mechanisms, little is known about the signal transduction in EC cells. We investigated the effects of adrenoceptor stimulation on 5-HT release from ileal tissue and intracellular calcium dynamics of epithelial cells in isolated ileal crypts in mice. Ileal tissues placed in organ bath were perfused with a buffered solution. Released 5-HT was measured using HPLC-ECD. Ileal crypts were isolated by collagenase digestion followed by moderate pipetting. Intracellular calcium dynamics were analyzed by digital video-imaging system using fura-2. NE, but not isoprenaline (Iso), induced 5-HT release from mouse ileal tissue. NE-induced 5-HT release was antagonized by yohimbine and rauwolscine, but not by prazosin and bunazosin. NE, but not Iso, also elicited a transient elevation of intracellular calcium in some EC cells. The effect of NE (1 microM) was slightly suppressed by prazosin and bunazosin, but was remarkably suppressed by yohimbine and rauwolscine. UK 14,304 and Clonidine at 10 microM significantly induced an increase in intracellular calcium concentration. NE-induced intracellular calcium dynamics was not significantly affected by timolol, Ro20-1724, rolipram and 8-bromo-cAMP. These results suggest that NE-induced 5-HT release from ileal EC cells is mediated predominantly via alpha 2-, but not beta-adrenoceptors, by a mechanism dependent on elevation of intracellular calcium concentration.
- Published
- 1998
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