Regional blood flow during digestion in the conscious dog

Gallavan, Robert H.; Chou, Chang-Hua; Kvietys, Peter R.; Sit, Siu Po

doi:10.1152/ajpheart.1980.238.2.h220

Cited by 62 publications

(62 citation statements)

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“…We noted a postprandial increase in GI blood flow in the CF piglets, as observed in adults (5,6,12,20,21) and neonates (3,22) of various species. Our baseline total GI blood flow and 30-min postprandial values were approximately 15 and 49% higher, respectively, than those obtained by Nowicki et al (4).…”

Section: Discussionsupporting

confidence: 59%

“…In HNF animals, elevations in heart rate and MABP again occurred presumably because of catecholamine release but potentially from the interaction of a number of variables (1 8); however, the lower baseline mean arterial blood pressure makes interpretation of the significance of the subsequent rise in blood pressure difficult. The CF piglets increased heart rate significantly in the early postprandial period consistent with a probable sympathomimetic response resulting from the anticipation and ingestion of food (6,19). Blood pressure and respiratory rates were not significantly affected by feeding or digestion (4), as observed by others.…”

Section: Discussionmentioning

confidence: 84%

“…These increases were confined primarily to the jejunal and ileal mucosal-submucosal tissues which are actively involved in nutrient absorption following a meal (23). Gallavan et al (6) demonstrated in adult dogs a significant increase in blood flow to the proximal small intestine 30 and 90 min after feeding and to the distal small intestine 90 min after feeding. This appeared to be the time sequence for intestinal transit and exposure of different segments to the digested products of food.…”

Section: Discussionmentioning

confidence: 98%

“…Studies in adult dogs have shown that hyperemia is most pronounced in the mucosal-submucosal layers of the small intestine because of their active involvement in digestion (5)(6)(7).…”

mentioning

confidence: 99%

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Postprandial Gastrointestinal Blood Flow and Oxygen Consumption: Effects of Hypoxemia in Neonatal Piglets

Szabo

Mayfield

et al. 1987

Pediatr Res

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ABSTRACT'. The effects of feeding on gastrointestinal (GI) perfusion and oxygen transport in hypoxemic neonates is unknown. We evaluated these effects in unanesthetized, spontaneously breathing newborn piglets by comparing three experimental groups: nine hypoxemic piglets (mean P a 0 2 26 torr) which were fed with formula, six hypoxemic piglets (mean PaOz 27 torr) which were not fed, and four normoxemic piglets (mean P a 0 2 79 torr) which were fed and served as controls. The control-fed group exhibited an increase in stomach and small intestinal mucosal-submucosal blood flow within 30 min following feeding which was significantly greater than that observed in the hypoxemic fed piglets. GI O2 delivery and 0, uptake rose significantly (p c 0.05) following a meal secondary to increases in total GI blood flow. Oxygen extraction was unchanged postprandially in the control group. In the hypoxemic nonfed piglets, total and regional GI blood flow was unaltered during hypoxemia. Reductions in arterial Oz content led to significant decreases in GI 0, delivery. Gastrointestinal oxygen uptake remained stable with a compensatory increase in GI O2 extraction. In the hypoxemic-fed piglets, hypoxia significantly decreased stomach blood flow and led to unchanged blood flow in the remainder of the GI tract. Significant reductions in arterial Oz content and GI O2 delivery were observed, accompanied by significant increases in O2 extraction. Hypoxemic fed animals did not exhibit the expected increase in OZ uptake to meet postprandial metabolic demands. When the hypoxemic insult was terminated, fed piglets demonstrated significant total and regional GI hyperemia leading to increased GI Oz uptake when compared with hypoxemic nonfed piglets. We conclude that in the presence of hypoxemia, the newborn piglet's GI tract is subject to decreased oxygen availability. In contrast to the fasted GI tract, the fed GI tract exhibits a significant hyperemia following a limited period of severe hypoxemia and an ability to increase oxygen uptake in an attempt to meet the demands of nutrient absorption. Oxygen uptake is not increased to the same extent as in normoxemic fed animals, thus the efficiency of these mechanisms in satisfying the postprandial O2 demand remains to be determined. (Pediatr Res 21: 93-98, 1987 Controversy exists as to the advisability of feeding infants soon after a hypoxic insult. Feeding is generally withheld in neonates during and for variable periods following hypoxemia because of the increased metabolic demand it places on a compromised gastrointestinal tract and an association with the development of necrotizing enterocolitis (1). However, a recent clinical study in preterm infants with oxygen and ventilator requirements has shown that early enteral feedings may prove beneficial and do not increase the incidence of necrotizing enterocolitis (2).The awake newborn animal meets the postprandial oxidative demands associated with nutrient absorption through enhanced GI oxygen extraction and selective GI hyperemia (3,4). Studi...

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 98%

“…Studies in adult dogs have shown that hyperemia is most pronounced in the mucosal-submucosal layers of the small intestine because of their active involvement in digestion (5)(6)(7).…”

mentioning

confidence: 99%

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Postprandial Gastrointestinal Blood Flow and Oxygen Consumption: Effects of Hypoxemia in Neonatal Piglets

Szabo

Mayfield

et al. 1987

Pediatr Res

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“…In addition to these organ-specific needs of postprandial hyperemia is the general requirement for increased oxygen delivery to the active digestive tissues. Although we did not specifically measure gastric and pancreatic blood flow (pancreatic arteries do originate from the superior mesenteric artery), postprandial increases in gastric and pancreatic blood flow have been studied in dogs (Gallavan et al, 1980;Kato et al, 1989). We suspect that the liver (independent of Python cardiovascular performance hepatic portal flow) and kidneys also experience significant postprandial increases in blood flow, stimulated by their increase in mass, metabolism and function (Secor and Diamond, 1995).…”

Section: Integration Of Postprandial Hyperemiamentioning

confidence: 99%

Prioritizing blood flow: cardiovascular performance in response to the competing demands of locomotion and digestion for the Burmese python,Python molurus

Secor

White

2010

Journal of Experimental Biology

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SUMMARYIndividually, the metabolic demands of digestion or movement can be fully supported by elevations in cardiovascular performance, but when occurring simultaneously, vascular perfusion may have to be prioritized to either the gut or skeletal muscles. Burmese pythons (Python molurus) experience similar increases in metabolic rate during the digestion of a meal as they do while crawling, hence each would have an equal demand for vascular supply when these two actions are combined. To determine, for the Burmese python, whether blood flow is prioritized when snakes are digesting and moving, we examined changes in cardiac performance and blood flow in response to digestion, movement, and the combination of digestion and movement. We used perivascular blood flow probes to measure blood flow through the left carotid artery, dorsal aorta, superior mesenteric artery and hepatic portal vein, and to calculate cardiac output, heart rate and stroke volume. Fasted pythons while crawling experienced a 2.7-and 3.3-fold increase, respectively, in heart rate and cardiac output, and a 66% decrease in superior mesenteric flow. During the digestion of a rodent meal equaling in mass to 24.7% of the snake's body mass, heart rate and cardiac output increased by 3.3-and 4.4-fold, respectively. Digestion also resulted in respective 11.6-and 14.1-fold increases in superior mesenteric and hepatic portal flow. When crawling while digesting, cardiac output and dorsal aorta flow increased by only 21% and 9%, respectively, a modest increase compared with that when they start to crawl on an empty stomach. Crawling did triggered a significant reduction in blood flow to the digesting gut, decreasing superior mesenteric and hepatic portal flow by 81% and 47%, respectively. When faced with the dual demands of digestion and crawling, Burmese pythons prioritize blood flow, apparently diverting visceral supply to the axial muscles.

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