| 1. |
- Florentzson, Malin, et al.
(författare)
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Low gastric acid and high plasma gastrin in high-anxiety Wistar Kyoto rats
- 2009
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 44:4, s. 401-407
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Wistar Kyoto (WKY) rats are more susceptible to stress-evoked ulcerations than Sprague-Dawley (SPD) rats. We have already demonstrated that gastrin cells are more active and ghrelin cells less active in WKY rats than in SPD rats. The purpose of this study was to compare endocrine cell activity and gastric acid output in WKY and SPD rats. Material and methods. Gastric acid output was determined in conscious rats with gastric fistula. Plasma gastrin and ghrelin levels were measured after an overnight fast. Acid secretagogues (gastrin, histamine and carbachol) were given by continuous subcutaneous infusion. Results. The volume of gastric juice, and the acidity and acid output were all significantly lower (p 0.05) in fasted WKY rats than in fasted SPD rats. Gastrin evoked a 4-fold (p 0.01) and 3-fold (p 0.05) increase in gastric acid output in SPD rats and WKY rats, respectively. Histamine raised the acid output 1.6-fold in SPD rats (p=0.06) and 3-fold in WKY rats (p 0.05), while carbachol failed to affect the acid output (weak increase, p 0.05). Fasting plasma ghrelin levels were 2-fold higher in SPD rats than in WKY rats (p 0.01) while fasting gastrin levels were 10-fold higher in WKY rats than in SPD rats (p 0.05). Neither the parietal-cell density nor the oxyntic mucosal thickness differed between the two strains. Conclusions. The results of the present study suggest that a high gastrin cell activity in WKY rats is secondary to a low gastric acidity. Whether the high gastrin cell activity is linked to susceptibility to stress ulcer in WKY rats warrants further investigation.
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| 2. |
- Janssen, Pieter, et al.
(författare)
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A Novel Method for Study of Gastric Mechanical Functions in Conscious Mice
- 2009
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Ingår i: Digestive Diseases and Sciences. - : Springer Science and Business Media LLC. - 0163-2116 .- 1573-2568. ; 54:2, s. 222-231
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Tidskriftsartikel (refereegranskat)abstract
- A novel method has been developed for simultaneous study of gastric emptying, antral motility, and gastric muscle tone in conscious mice. Intragastric pressure was measured during infusion of an X-ray-opaque, viscous meal through a chronically implanted gastric fistula (0.25 ml/min). Compared with vehicle treatment, molsi-domine (nitric oxide donor) and atropine (muscarinic receptor antagonist) treatment significantly reduced the area under the intragastric pressure curve (AUC) by 37 +/- 4% and 35 +/- 3%, respectively, (mean +/- S.E.M.) whereas N-G-nitro-L-arginine methyl ester (L-NAME; nitric oxide synthase inhibitor) significantly increased the AUC by 20 +/- 3%. Atropine also significantly reduced the frequency and amplitude of stomach contraction-induced intragastric pressure waves while molsidomine only reduced the frequency. Gastric emptying, as assessed by X-ray imaging, was significantly delayed after L-NAME and atropine treatment. This methodology is the first to enable simultaneous assessment of gastric emptying, antral motility, and gastric tone in conscious mice and confirmed the important role of nitrergic and cholinergic innervation.
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| 3. |
- Janssen, Pieter, et al.
(författare)
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A novel method to assess gastric accommodation and peristaltic motility in conscious rats
- 2008
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 43:1, s. 34-43
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To simultaneously study gastric accommodation and peristaltic motility in the whole stomach of conscious rats by measuring intragastric pressure (IGP) during test-meal infusion. Material and methods. After an overnight fast, a test-meal infusion system and a catheter to measure IGP were connected to a chronically implanted gastric fistula. IGP was measured during infusion of an X-ray-opaque, non-nutritious viscous test meal (0.25-2 ml min(-1)); gastric motility and emptying were assessed by X-ray fluoroscopy. Peristaltic motility-induced IGP waves were quantified as a motility index (wave amplitude divided by wavelength). Experiments were performed in Sprague-Dawley (SD) rats and in the high-anxiety Wistar Kyoto (WKY) rats. Moreover, the effects of 30 mg kg(-1) N-G-nitro-L-arginine methyl ester (L-NAME), 1 mg kg(-1) atropine or 20 mg kg(-1) molsidomine were tested in SD rats. Results. Compared with SD rats, IGP increased significantly faster during stomach distension in WKY rats, indicating impaired accommodation in the latter strain. Motility indices did not differ between the two strains. L-NAME significantly increased IGP during stomach distension, indicating decreased gastric accommodation. However, no change in motility indices was observed with L-NAME. Treatment with atropine significantly increased IGP and decreased motility indices, indicating decreased gastric accommodation and motility. Molsidomine significantly decreased IGP during stomach distension but did not affect motility. The results correspond to X-ray observations, and confirm literature data. Conclusions. We conclude that IGP measurement during test-meal infusion represents an efficient and novel method to compare gastric accommodation and peristaltic motility in the whole stomach of conscious rats.
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| 4. |
- Janssen, Pieter, et al.
(författare)
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Effect of Muscarinic and Nicotinic Receptor Antagonism on Rat Gastric Motor Activity
- 2010
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Ingår i: Pharmacology. - : S. Karger AG. - 0031-7012 .- 1423-0313. ; 85:5, s. 272-279
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Our aim was to investigate whether muscarinic and nicotinic receptors mediate nitric oxide release during motor events in the rat stomach. Methods: Isolated rat stomach volume changes were monitored in an organ bath setup with an intragastric balloon coupled to a barostat and studied in basal conditions and during electrical vagal stimulation (EVS). In conscious rats, the intragastric pressure (IGP) was measured during test meal infusion. Results: In the presence of N-G-nitro-L -arginine methyl ester (L-NAME; 0.1 mmol/l), EVS induced significant gastric contractions (mean +/- SEM = 0.27 +/- 0.04 ml; n = 6) that could be blocked by atropine (3 mu mol/l) and hexamethonium (0.1 mmol/l). In the presence of atropine and/or hexamethonium, EVS-induced relaxations could not be blocked by L-NAME, while exogenous nitric oxide could still relax the stomach. In conscious rats, atropine (1 mg kg(-1)) initially decreased IGP, while during further distension it increased IGP. In the presence of L -NAME (30 mg kg(-1)) atropine consistently decreased IGP.
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