Stimulation of neurons in rat ARC inhibits gastric acid secretion via hypothalamic CRF1/2- and NPY-Y1 receptors

2003 ◽  
Vol 285 (6) ◽  
pp. G1075-G1083 ◽  
Author(s):  
Johannes J. Tebbe ◽  
Silke Mronga ◽  
Martin K.-H. Schäfer ◽  
Jens Rüter ◽  
Peter Kobelt ◽  
...  

Neuropeptide Y (NPY) neuronal projections from the arcuate nucleus (ARC) have been proposed to target corticotropin-releasing factor (CRF)-positive neurons in the paraventricular nucleus (PVN) as part of the ARC-PVN axis. The existence of a positive feedback loop involving CRF receptors in the PVN has been suggested. Exogenous NPY and CRF in the PVN have been shown to inhibit gastric acid secretion. Recently, we have demonstrated that activation of ARC neurons inhibits gastric acid secretion via vagal pathways. To what extent NPY- and CRF-mediated mechanisms in the PVN contribute to the CNS modulation of gastric acid secretion is still an open question. In the present study, we performed consecutive bilateral microinjections of antagonists to NPY receptor subtypes Y1 and Y2 and to CRF1/2 receptors in the PVN and of the excitatory amino acid kainate in the ARC to assess the role of NPY- and CRF-mediated mechanisms in the kainate-induced effects on gastric acid secretion. Gastric acid secretion was measured at the basal condition and during pentagastrin (16 μg/kg body wt) stimulation. Microinjection of vehicle in the PVN and kainate in the ARC decreased gastric acid secretion. Microinjection of the specific NPY-Y1 receptor antagonist BIBP-3226 (200 pmol) and the nonspecific CRF1/2 antagonist astressin (30 pmol) in the PVN abolished the inhibitory effect of neuronal activation in the ARC by kainate on gastric acid secretion. The CRF antagonist astressin was more effective. Pretreatment with the NPY-Y2 receptor antagonist BIIE-0246 (120 pmol) in the PVN had no significant effect. Our results indicate that activation of neurons in the ARC inhibits gastric acid secretion via CRF1/2 and NPY-Y1 receptor-mediated pathways in the PVN.

1999 ◽  
Vol 276 (2) ◽  
pp. G550-G555 ◽  
Author(s):  
Xiao-Tuan Zhao ◽  
John H. Walsh ◽  
Helen Wong ◽  
Lijie Wang ◽  
Henry C. Lin

Fat in small intestine decreases meal-stimulated gastric acid secretion and slows gastric emptying. CCK is a mediator of this inhibitory effect (an enterogastrone). Because intravenously administered peptide YY (PYY) inhibits acid secretion, endogenous PYY released by fat may also be an enterogastrone. Four dogs were equipped with gastric, duodenal, and midgut fistulas. PYY antibody (anti-PYY) at a dose of 0.5 mg/kg or CCK-A receptor antagonist (devazepide) at a dose of 0.1 mg/kg was administered alone or in combination 10 min before the proximal half of the gut was perfused with 60 mM oleate or buffer. Acid secretion and gastric emptying were measured. We found that 1) peptone-induced gastric acid secretion was inhibited by intestinal fat ( P < 0.0001), 2) inhibition of acid secretion by intestinal fat was reversed by CCK-A receptor antagonist ( P < 0.0001) but not by anti-PYY, and 3) slowing of gastric emptying by fat was reversed by CCK-A antagonist ( P< 0.05) but not by anti-PYY. We concluded that inhibition of peptone meal-induced gastric acid secretion and slowing of gastric emptying by intestinal fat depended on CCK but not on circulating PYY.


2005 ◽  
Vol 289 (1) ◽  
pp. G64-G69 ◽  
Author(s):  
Shinichi Kato ◽  
Eitaro Aihara ◽  
Katsuhide Yoshii ◽  
Koji Takeuchi

We examined the role of prostaglandin E (EP) receptor subtypes in the regulation of gastric acid secretion in the rat. Under urethane anesthesia, the stomach was superfused with saline, and the acid secretion was determined at pH 7.0 by adding 50 mM NaOH. The acid secretion was stimulated by intravenous infusion of histamine or pentagastrin. Various EP agonists were administered intravenously, whereas EP antagonists were given subcutaneously 30 min or intravenously 10 min before EP agonists. PGE2 suppressed the acid secretion stimulated by either histamine or pentagastrin in a dose-dependent manner. The acid inhibitory effect of PGE2 was mimicked by sulprostone (EP1/EP3 agonist) but not butaprost (EP2 agonist) or AE1–329 (EP4 agonist). The inhibitory effect of sulprostone, which was not affected by ONO-8711 (EP1 antagonist), was more potent against pentagastrin- (50% inhibition dose: 3.6 μg/kg) than histamine-stimulated acid secretion (50% inhibition dose: 18.0 μg/kg). Pentagastrin increased the luminal release of histamine, and this response was also inhibited by sulprostone. On the other hand, AE1–329 (EP4 agonist) stimulated the acid secretion in vagotomized animals with a significant increase in luminal histamine. This effect of AE1–329 was totally abolished by cimetidine as well as AE3–208 (EP4 antagonist). These results suggest that PGE2 has a dual effect on acid secretion: inhibition mediated by EP3 receptors and stimulation through EP4 receptors. The former effect may be brought about by suppression at both parietal and enterochromaffin-like cells, whereas the latter effect may be mediated by histamine released from enterochromaffin-like cells.


1988 ◽  
Vol 62 (1) ◽  
pp. 91-94
Author(s):  
R. C. Stoddart ◽  
D. W. T. Crompton

ABSTRACTA technique is described whereby young adultMoniliformis moniliformis, aged up to 7 days, can be transferred via the oral route from one rat to another. The method is dependent on giving the recipient rats a dose of Cimetidine (0·25 ml/250 g body weight of a solution containing 950 mg/ml) 1 h before transfer. Cimetidine functions as an H2-receptor antagonist and gastric acid secretion in the rat is inhibited temporarily. The technique does not appear to interfere with the reproductive biology of the parasite.


1992 ◽  
Vol 263 (3) ◽  
pp. G287-G292 ◽  
Author(s):  
K. C. Lloyd ◽  
H. E. Raybould ◽  
J. H. Walsh

The purpose of this study was to determine whether selective antagonism of type "A" cholecystokinin (CCK) receptors blocks inhibition of gastric acid secretion produced by CCK and whether this inhibition is mediated through either a somatostatin-dependent pathway or a vago-vagal reflex. Intravenous infusion of CCK (0.04-10 nmol.kg-1.h-1) dose dependently inhibited pentagastrin-stimulated gastric acid secretion in urethan-anesthetized rats, with a 50% inhibitory dose of 0.9 nmol.kg-1.h-1 and a maximum inhibition of approximately 50%. Blockade of type A CCK receptors using the selective type A receptor antagonist MK-329 completely reversed the inhibitory effect produced by a maximal dose (4 nmol.kg-1.h-1) of CCK. Immunoneutralization of endogenous somatostatin by administration of somatostatin monoclonal antibody abolished the inhibition produced by CCK. Concentrations of somatostatin in portal venous plasma were significantly increased after CCK administration; the increase in somatostatin was blocked by pretreatment with MK-329. In contrast, CCK-induced inhibition of gastric acid secretion was unaltered after perivagal capsaicin treatment. These results indicate that CCK inhibits gastric acid secretion in rats by activation of type A CCK receptors and through release of endogenous somatostatin.


1990 ◽  
Vol 35 (4) ◽  
pp. 439-443 ◽  
Author(s):  
Robert A. Hammer ◽  
Richard E. Hernandez ◽  
Ann Shepard

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