scholarly journals EFFECTS OF LENGTH AND REGION OF SMALL INTESTINAL GLUCOSE EXPOSURE ON BLOOD PRESSURE, SUPERIOR MESENTERIC ARTERY BLOOD FLOW AND PLASMA NORADRENALINE IN HEALTHY OLDER PARTICIPANTS

2018 ◽  
pp. 1-7
Author(s):  
R.S. Rigda ◽  
L.G. Trahair ◽  
T. Wu ◽  
T.J. Little ◽  
K. Lange ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Small Intestine ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Plasma Noradrenaline ◽  
Glucose Exposure ◽  
Small Intestinal ◽  
Mesenteric Artery Blood Flow ◽  
Occluding Balloon

Background: A substantial postprandial reduction in blood pressure (BP), triggered by the interaction of nutrients with the small intestine and associated with increases in heart rate (HR) and splanchnic blood flow, occurs frequently in healthy older people. Objective: The aim of this study was to determine whether these responses are influenced by the length and/or region of small intestine exposed to nutrients. Design: Randomized, single blind study. Setting: Clinical research laboratory. Participants: Ten healthy older participants (9M, 1F; age 65 – 79 yr). Intervention: On 3 separate study days, participants were intubated with a small intestinal catheter incorporating two duodenal infusion ports and an aspiration port, as well as an occluding balloon, which was positioned ~ 60 cm beyond the pylorus. Each participant then received a 60 min (t = 0 – 60 min) intraluminal infusion of glucose (3 kcal/min) into either the proximal (< 60 cm “GP”), or the distal (> 70 cm “GD”), or both (i.e. proximal and distal “GPD”), small intestinal segments. Measurements: BP, HR (automated device), superior mesenteric artery (SMA) blood flow (Doppler ultrasound) and plasma noradrenaline (NA). Results: Small intestinal glucose infusion was associated with reductions in systolic (GP: P = 0.004, GD: P = 0.001, GPD: P = 0.001) and diastolic (GP: P = 0.007, GD: P = 0.004, GPD: P = 0.003) BP and increases in HR (GP: P = 0.001, GD: P = 0.001, GPD: P = 0.002) and plasma NA (GP: P = 0.001, GD: P = 0.002, GPD: P = 0.001), without any difference between the three days. Conclusion: In healthy older participants, the effects of small intestinal glucose to decrease BP and increase SMA flow in healthy older participants appear to be independent of the region, or length, of small intestine exposed.

Microsphere method in measurement of blood flow to wall layers of small intestine

1986 ◽  
Vol 250 (5) ◽  
pp. G670-G678 ◽  
Author(s):  
E. Dregelid ◽  
S. Haukaas ◽  
S. Amundsen ◽  
G. E. Eide ◽  
O. Soreide ◽  
...  
Keyword(s):  
Blood Flow ◽  
Small Intestine ◽  
Tissue Distribution ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Consistent Difference ◽  
Local Blood Flow ◽  
Microsphere Method ◽  
Small Intestinal ◽  
Log Linear

Microspheres of 10.90 +/- 0.65 micron (SD) were injected in the superior mesenteric artery of cats and their intramural distribution and diameter in the small intestine were studied microscopically under basal conditions and after vasodilation by isoproterenol. Approximately 2% of the spheres were shunted through the small intestinal vasculature and could be recovered in the liver. Analysis of the tissue distribution suggested that all spheres arrested in villi represented villous blood flow, spheres arrested in the crypt layer represented flow to the crypts, and the majority of microspheres trapped in the submucosa also represented crypt flow. Nutritive blood flow to the submucosa constituted only 1.5% of total intestinal flow. Log-linear analyses identified factors responsible for sphere distribution, including effects of sphere size, isoproterenol treatment, and local blood flow or vascular resistance. Spheres with diameters greater than 11.08 micron had 1.35 times larger odds than smaller spheres to embolize in the muscularis rather than in the mucosa, but no consistent difference between diameter profiles in the crypts and villi was found. With this reservation, 11-micron spheres seem to be appropriate for measuring blood flow to the muscle, crypt, and villous layers of the small intestine.

Differential responses in superior mesenteric artery blood flow may explain the variant pressor responses to clonidine in two groups with sympathetic denervation

1992 ◽  
Vol 83 (1) ◽  
pp. 59-64 ◽  
Author(s):  
T. N. Thomaides ◽  
K. Ray Chaudhuri ◽  
S. Maule ◽  
C. J. Mathias
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Multiple System Atrophy ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Autonomic Failure ◽  
Pure Autonomic Failure ◽  
Artery Blood Flow ◽  
Control Subjects ◽  
Mesenteric Artery Blood Flow

1. Measurement of superior mesenteric artery blood flow along with systemic and regional haemodynamic changes in blood pressure, heart rate, cardiac index, forearm blood flow, digital skin blood flow and index finger temperature were made before and after administration of clonidine (2 μg/kg body weight intravenously) in 10 patients with multiple-system atrophy, 10 patients with pure autonomic failure and 15 age-matched healthy control subjects. 2. After clonidine, blood pressure fell in patients with multiple-system atrophy and control subjects but not in patients with pure autonomic failure. 3. Resting superior mesenteric artery blood flow was similar in patients with multiple-system atrophy and control subjects, but was higher in patients with pure autonomic failure. The fall in blood pressure after clonidine was accompanied by active dilatation of the superior mesenteric artery in patients with multiple-system atrophy and control subjects. This did not occur in patients with pure autonomic failure. 4. After clonidine, there was a fall in cardiac index in patients with multiple-system atrophy. 5. After clonidine, changes in other haemodynamic parameters were not significant in any group, except for a fall in forearm blood flow and a rise in index finger temperature in control subjects. 6. We conclude that after clonidine there are differential superior mesenteric artery blood flow responses in the two groups with autonomic failure (multiple-system atrophy and pure autonomic failure). These may relate to differences in the site of the sympathetic lesion, which is considered to be mainly central in multiple-system atrophy but peripheral in pure autonomic failure. The blood pressure responses to clonidine in the two groups may be largely dependent on changes in superior mesenteric artery blood flow.

Effects of small intestinal glucose load on blood pressure, splanchnic blood flow, glycemia, and GLP-1 release in healthy older subjects

2011 ◽  
Vol 300 (6) ◽  
pp. R1524-R1531 ◽  
Author(s):  
Lora Vanis ◽  
Diana Gentilcore ◽  
Christopher K. Rayner ◽  
Judith M. Wishart ◽  
Michael Horowitz ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Splanchnic Blood Flow ◽  
Glucose Load ◽  
Postprandial Hypotension ◽  
Older Subjects ◽  
Small Intestinal ◽  
Artery Flow

Postprandial hypotension is an important problem, particularly in the elderly. The fall in blood pressure is dependent on small intestinal glucose delivery and, possibly, changes in splanchnic blood flow, the release of glucagon-like peptide-1 (GLP-1), and sympathetic nerve activity. We aimed to determine in healthy older subjects, the effects of variations in small intestinal glucose load on blood pressure, superior mesenteric artery flow, GLP-1, and noradrenaline. Twelve subjects (6 male, 6 female; ages 65–76 yr) were studied on four separate occasions, in double-blind, randomized order. On each day, subjects were intubated via an anesthetized nostril, with a nasoduodenal catheter, and received an intraduodenal infusion of either saline (0.9%) or glucose at a rate of 1, 2, or 3 kcal/min (G1, G2, G3, respectively), for 60 min ( t = 0–60 min). Between t = 0 and 60 min, there were falls in systolic and diastolic blood pressure following G2 and G3 ( P = 0.003 and P < 0.001, respectively), but no change during saline or G1. Superior mesenteric artery flow increased slightly during G1 ( P = 0.01) and substantially during G2 ( P < 0.001) and G3 ( P < 0.001), but not during saline. The GLP-1 response to G3 was much greater ( P < 0.001) than to G2 and G1. Noradrenaline increased ( P < 0.05) only during G3. In conclusion, in healthy older subjects the duodenal glucose load needs to be > 1 kcal/min to elicit a significant fall in blood pressure, while the response may be maximal when the rate is 2 kcal/min. These observations have implications for the therapeutic strategies to manage postprandial hypotension by modulating gastric emptying.

Superior Mesenteric Artery Blood Flow Modifications During Off-Pump Coronary Surgery

2006 ◽  
Vol 82 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Giuseppe Fiore ◽  
Nicola Brienza ◽  
Pasquale Cicala ◽  
Pasquale Tunzi ◽  
Nicola Marraudino ◽  
...  
Keyword(s):  
Blood Flow ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Coronary Surgery ◽  
Artery Blood Flow ◽  
Off Pump ◽  
Mesenteric Artery Blood Flow

Hemodynamic responses to glycols and to hemolysis

1969 ◽  
Vol 47 (6) ◽  
pp. 563-569 ◽  
Author(s):  
Keith MacCannell
Keyword(s):  
Blood Flow ◽  
Superior Mesenteric Artery ◽  
Renal Blood Flow ◽  
Mesenteric Artery ◽  
Direct Injection ◽  
Artery Blood Flow ◽  
Passive Response ◽  
Flow Through ◽  
Vascular Beds ◽  
Mesenteric Artery Blood Flow

Ethylene and propylene glycol both decrease renal blood flow in dogs while increasing flow through the superior mesenteric artery. The decrease in renal blood flow is not a passive response to dilatation of major vascular beds since it precedes the increment in superior mesenteric arterial flow and since it can be duplicated by direct injection of glycols into the renal artery. These rheological changes in response to glycols are at least partly due to hemolysis since intravenous injection of plasma from hemolyzed blood or of crystalline hemoglobin produces the same pattern of response, which is not blocked by phenoxybenzamine. However, the production of hemoglobinemia may not be the sole explanation for the vascular responses to the glycols, since a concentration of 2 %, which does not induce detectable hemolysis, still produces the characteristic increase in superior mesenteric artery blood flow.

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