Intrinsic regulation of functional blood flow and water absorption in canine colon.

Granger, D. Neil; Kvietys, Peter R.; Mailman, David; Richardson, P. D.

doi:10.1113/jphysiol.1980.sp013445

Cited by 22 publications

(14 citation statements)

References 18 publications

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“…9 Sieber C, Beglinger K, Jaeger K, Hildebrand P, Stalder GA. Divergent rates ofgastric emptying of different food components and their subsequent hyperaemic responses are well established. 4 Indeed, in the cited paper by Moneta et al3 the hyperaemic effect oforal carbohydrates was the fastest one, whereas fat induced the most pronounced response in agreement with our hypothesis. These findings are not a contradiction to the unpublished studies by Qamar, where he tested the hypaeremic response to both liquid and solid oral meals.…”

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confidence: 80%

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Beglinger¹,

Sieber²,

Stalder³

et al. 1992

Gut

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Indeed, in the cited paper by Moneta et al.3 the hyperaemic effect oforal carbohydrates was the fastest one, whereas fat induced the most pronounced response in agreement with our hypothesis. These findings are not a contradiction to the unpublished studies by Qamar, where he tested the hypaeremic response to both liquid and solid oral meals. Indeed, in our own publication,' the response to oral liquid and solid food was tested and shown in Figure 1, giving similar amounts of responses with the exception that the maximal response was observed 15 minutes later for the solid meal, probably owing to slower gastric emptying. The aim of our studies, however, was to gain further insight into how different food components elicit different degrees of intestinal hyperaemia. To do so, we examined the major food components in an isocaloric and isoosmotic manner by perfusing them into the duodenum to overcome the confounding effects of divergent rates of gastric emptying.We cannot accept the hypothesis that differences between our results and those of Qamar et al2 were due to the addition of the water soluble non-absorbable marker polyethylene glycol (PEG). Non-absorbable polysaccharides such as pectin may delay gastric emptying and glucose absorption.I Nevertheless, the concentrations given were higher than our PEG4000 concentration of 2 g/l. Interestingly, the authors of the cited study' used PEG4000 at a concentration of 5 g/l as an inert marker to examine the role of pectin.Finally, animal studies have shown that PEG at high osmolarities (3000 mosm/l) by itself increases splanchnic blood flow.4 Concentrations below 1500 mmol/l had no effect. In fact, postprandial osmolarities are much lower and in the range we tested with the 560 mM saline solution, where we found no change in superior mesenteric artery blood flow. As we added PEG at the same concentration in all our intraduodenal perfusion experiments, differences in hyperaemic responses to different food components cannot be caused by PEG; We are unable to comment upon unpublished data and therefore hope that these studies will be published soon to help fruitful discussions.

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confidence: 80%

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Beglinger¹,

Sieber²,

Stalder³

et al. 1992

Gut

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“…This latter lack of effect does not mean that ketanserin is not a 5-HT2-receptor blocker. It has been shown that the effect of 5-HT on the intestinal vascular bed is complex (Granger, Richardson, Kvietys & Mortillaro, 1980 (Falk, Kaijser, Myrvold & Haglund, 1980 pressure and pulmonary vascular resistance, a rapid and reversible drop in systemic arterial blood pressure without significant changes in aortic blood flow. After a few minutes, arterial blood pressure is more or less restored while aortic blood flow is significantly reduced.…”

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confidence: 99%

The role of 5‐hydroxytryptamine in the feline response to intravenous infusion of live E. coli

Arvidsson¹,

Falk²,

Haglind³

et al. 1983

British J Pharmacology

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A standardized septic shock was induced in cats by intravenous infusion of a live E. coli bacteria strain. The bacterial infusion induced a rapid haemodynamic response characterized mainly by a pulmonary arterial hypertension and a late phase characterized by systemic hypotension and hypodynamic circulation. Systemic arterial, pulmonary arterial, portal venous, left atrial pressures, max inspiratory‐expiratory pressure difference in the trachea, aortic and intestinal blood flows were monitored. Arterial blood samples were taken for recording the number of circulating platelets and white blood cells and for determining the acid‐base balance. The effect of pretreatment with ketanserin, a specific 5‐hydroxytryptamine2 (5‐HT2)‐receptor blocker on these haemodynamic reactions was studied. In short term experiments on non‐bacteriaemic control cats, ketanserin prevented the pulmonary hypertension induced by intravenous 5‐HT infusions but not the increase in intestinal blood flow. Ketanserin induced a reduction of total peripheral (including intestinal) vascular resistance to blood flow but had no effect on aortic blood flow. After infusion of bacteria, ketanserin pretreated cats were more hypotensive due to a relative peripheral dilatation of the resistance vessels. Ketanserin pretreatment had no effect on the pulmonary vascular reactions, the tracheal pressure difference or the number of circulating platelets or white blood cells. Thus, except for a more pronounced hypotension early after bacterial infusion, ketanserin pretreatment did not influence the haemodynamic response. It is concluded that 5‐HT is not of significant importance in the pathogenesis of the haemodynamic reactions following experimental bacteraemia.

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“…This finding may at least partly be explained by the redistribution of blood flow towards the mucosa noted in the present experiments and in similar experiments reported by Fevang et al [19] . These observations most likely reflect autoregulatory mechanisms reported to be present both in the cat small intestine and in the dog colon [27,28] , but it is noteworthy that they are intact also during strangulation obstruction and may be important for tissue protection in this situation.…”

Section: Discussionmentioning

confidence: 89%

Lactate and Glycerol Released to the Intestinal Lumen Reflect Mucosal Injury and Permeability Changes Caused by Strangulation Obstruction

Juel¹,

Solligård

Skogvoll

et al. 2007

Eur Surg Res

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Background: The present study evaluates whether microdialysis of glycerol and lactate reflects mucosal injury and permeability changes after strangulation obstruction of the pig small intestine. Methods: Strangulation obstruction was induced by tightening a rubber band around a small bowel loop until its venous pressure increased to a level just below diastolic aortic pressure (partial strangulation), or further until cessation of flow in the main feeding artery (total strangulation). Mucosal injury and permeability of marker molecules from blood to lumen and vice versa was compared to release of glycerol and lactate to the intestinal lumen. Results: Mucosal injury, hyperpermeability, and release of glycerol were more pronounced after total than after partial strangulation. In animals with partial strangulation there was a complete restitution of the surface epithelium, and luminal glycerol and lumen-to-blood permeability of polyethylene glycol 4000 remained low. Such animals showed a sustained elevation of lactate and blood-to-lumen permeability of fluorescein isothiocyanate dextran after 2 h of partial strangulation, but a decline to baseline levels of these parameters in animals with 1 h partial strangulation. Conclusion: Microdialysis of lactate and glycerol in the intestinal lumen may be used to assess structural and functional changes of the intestinal mucosa after strangulation obstruction.

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Intrinsic regulation of functional blood flow and water absorption in canine colon.

Cited by 22 publications

References 18 publications

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The role of 5‐hydroxytryptamine in the feline response to intravenous infusion of live E. coli

Lactate and Glycerol Released to the Intestinal Lumen Reflect Mucosal Injury and Permeability Changes Caused by Strangulation Obstruction

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