- 作者: Kai-Han Huang; Chia-Chieh Chang; Jau-Der Ho; Ruey-Hwa Lu; Li Hsueh Tsai
- 作者服務機構: Department of Ophthalmology, Taipei Medical University Hospital, Taipei, Taiwan, R.O.C.
- 中文摘要: --
- 英文摘要:
Background: Taurine has chemical structure similar to an inhibitory neurotransmitter, γ-aminobutyric acid
(GABA). Previous studies on GABA in the stomach suggest GABAergic neuron is involved
in acid secretion, but the effects of taurine are poor understood.
Methods: The effects of taurine on acid secretion, signal transduction, and localization of taurinergic
neurons were determined in the rat stomach using everted whole stomach, RIA kit and
immunohistochemical methods.
Results: We used antibodies against taurine-synthesizing enzyme, cysteine sulfuric acid decarboxylase
(CSAD), and taurine. CSAD- and taurine-positive cells were found in the muscle and mucosal
layers. Distributions of CSAD- and taurine-positive cells in both mucosal and muscle layers
were heterogeneous in the stomach. Taurine at 10-9~10-4 M induced acid secretion, and the
maximum secretion was at 10-5 M, 1.6-fold higher than the spontaneous secretion. Taurineinduced
acid secretion was completely inhibited by bicuculline and atropine but not by
cimetidine, proglumide, or strychnine. Atropine and tetrodotoxin (TTX) completely inhibited
the acid secretion induced by low concentrations of taurine and partially inhibited induced by
high concentrations. Verapamil, a calcium blocker agent, inhibited acid output elicited by
taurine. We assumed all Ca2+ channels involved in the response to these secretagogues were
equally affected by verapamil. Intracellular cAMP (adenosine 3', 5’-monophosphat) in the
stomach significantly increased with taurine treatment in a dose-dependent manner. High
correlation (r=0.859, p<0.001) of taurine concentrations with cAMP was observed.
Conclusions: Our results demonstrated for the first time in taurine-induced acid secretion due to increase
intracellular calcium may act through the A type of GABA receptors, which are mainly located
on cholinergic neurons though cAMP pathway and partially on nonneuronal cells in the rat
stomach. - 中文關鍵字: --
- 英文關鍵字: --