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- Andersson, K, et al.
(author)
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Gastric acid secretion after depletion of enterochromaffin-like cell histamine. A study with a-fluoromethylhistidine in rats
- 1996
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In: Scandinavian Journal of Gastroenterology. - 1502-7708. ; 31:1, s. 24-30
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Journal article (peer-reviewed)abstract
- BACKGROUND: Histamine is thought to play a central role in the regulation of gastric acid secretion. In the rat oxyntic mucosa most of the histamine is synthesized and stored in enterochromaffin-like (ECL) cells, and the rest resides in mast cells. The present study examines the role of ECL-cell histamine in the control of acid secretion in the intact, conscious rat. METHODS: Rats were treated with alpha-fluoromethylhistidine (alpha-FMH) to inhibit histamine synthesis. alpha-FMH was given by continuous subcutaneous infusion (3 mg/kg/h) for up to 9 days. An additional oral dose of alpha-FMH (50 mg/kg) was given 2 h before each acid secretion test. Acid secretion was studied in pylorus-ligated rats and in chronic gastric fistula rats stimulated with histamine, gastrin-17, or insulin after 2-6 days of alpha-FMH infusion. RESULTS: Treatment with alpha-FMH lowered oxyntic mucosal histamine synthesis by 80%. From previous observations this is thought to reflect depletion of histamine from the ECL cells. The remaining 20% resides in mucosal and submucosal mast cells, which seem to be resistant to alpha-FMH. Basal acid secretion was inhibited by more than 60% after alpha-FMH treatment and by more than 80% by ranitidine. Histamine-stimulated secretion was unaffected by alpha-FMH and abolished by the histamine H2-receptor antagonist ranitidine. The acid response to gastrin-17 was almost abolished in histamine-depleted rats and abolished by ranitidine. Vagally induced acid secretion (provoked by the injection of insulin or by pylorus ligation) was unaffected by alpha-FMH treatment but abolished by ranitidine and by the muscarinic M1-receptor antagonist pirenzepine. CONCLUSION: The results suggest that gastrin stimulates acid secretion by releasing histamine from ECL cells. Vagally induced acid secretion is also dependent on a histaminergic pathway but not on ECL-cell histamine.
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- Gulda, K, et al.
(author)
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Quadrupole deformed and octupole collective bands in Ra-228
- 1998
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In: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 636:1, s. 28-46
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Journal article (peer-reviewed)abstract
- Spins and parities for collective states in Ra-228 have been determined from conversion electron measurements with a mini-orange beta spectrometer. The fast-timing beta gamma gamma(t) method has been used to measure lifetimes of T-1/2 = 550(20) ps and 181
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