Effects of variations in duodenal glucose load on blood pressure, heart rate, superior mesenteric artery blood flow and plasma noradrenaline in healthy young and older subjects

2011 ◽  
Vol 122 (6) ◽  
pp. 271-279 ◽  
Author(s):  
Laurence G. Trahair ◽  
Lora Vanis ◽  
Diana Gentilcore ◽  
Kylie Lange ◽  
Christopher K. Rayner ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Clinical Problem ◽  
Vascular Conductance ◽  
Female Age ◽  
Older Subjects ◽  
Young Subjects

PPH (postprandial hypotension), leading to increased morbidity and mortality, is an important clinical problem, particularly in the elderly and individuals with autonomic dysfunction. The magnitude of the postprandial fall in BP (blood pressure) appears to be dependent on the rate of nutrient entry into the small intestine and may be related to changes in splanchnic blood flow and sympathetic nerve activity. We aimed at determining the comparative effects of different ID (intraduodenal) glucose loads on BP, HR (heart rate), SMA (superior mesenteric artery) flow and vascular conductance and plasma NA (noradrenaline) in ‘young’ and ‘older’ subjects. A total of 12 ‘young’ (six male and six female; age, 22.2±2.3 years) and 12 ‘older’ (six male and six female; age, 68.7±1.0 years) subjects, the latter who have been studied previously [Vanis, Gentilcore, Rayner, Wishart, Horowitz, Feinle-Bisset and Jones (2011) Am. J. Physiol. Regul. Integr. Comp. Physiol., 300, R1524–R1531], had measurements of BP, HR, SMA flow and plasma NA before, and during, ID infusions of glucose at 1, 2 or 3 kcal/min (‘G1’, ‘G2’ and ‘G3’) (where 1 kcal≈4.184 J), or ‘S’ (saline) for 60 min. In ‘young’ subjects, there was no change in BP during any of the four infusions. In contrast, in ‘older’ subjects, SBP (systolic BP) fell during ‘G2’, and ‘G3’ (P<0.005 for both), but not during ‘S’ or ‘G1’. In ‘young’ and ‘older’ subjects HR increased during ‘G2’ (P<0.05) and ‘G3’ (P<0.001), a response that was greater (P<0.05) in the young, but not during ‘S’ or ‘G1’. The rise in SMA flow and vascular conductance in response to ID glucose were load-dependent in both ‘young’ and ‘older’ subjects (P<0.001 for all), with no difference between them. Plasma NA rose in response to ‘G2’ and ‘G3’ (P<0.05) in the young, but in ‘G3’ (P<0.05) only in the ‘older’ subjects, with no difference between them. Hence, in response to small intestinal glucose infusions at 1, 2 and 3 kcal/min, ‘older’, but not ‘young’, subjects exhibit a comparable fall in BP in response to the two higher glucose loads, which may reflect an inadequate, compensatory, rise in HR, in the ‘older’ subjects, but not a greater increase in SMA conductance.

scholarly journals Effects of intraduodenal administration of the artificial sweetener sucralose on blood pressure and superior mesenteric artery blood flow in healthy older subjects

2018 ◽  
Vol 108 (1) ◽  
pp. 156-162 ◽  
Author(s):  
Hung T Pham ◽  
Julie E Stevens ◽  
Rachael S Rigda ◽  
Liza K Phillips ◽  
Tongzhi Wu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Blood Glucose ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Saline Control ◽  
Artificial Sweeteners ◽  
Artificial Sweetener ◽  
Older Subjects ◽  
Intraduodenal Administration

ABSTRACTBackgroundPostprandial hypotension (PPH) occurs frequently, particularly in older people and those with type 2 diabetes, and is associated with increased morbidity and mortality. The magnitude of the decrease in blood pressure (BP) induced by carbohydrate, fat, and protein appears to be comparable and results from the interaction of macronutrients with the small intestine, including an observed stimulation of mesenteric blood flow. It is not known whether artificial sweeteners, such as sucralose, which are widely used, affect BP.ObjectiveThe aim of this study was to evaluate the effects of intraduodenal sucralose on BP and superior mesenteric artery (SMA) blood flow, compared with intraduodenal glucose and saline (control), in healthy older subjects.DesignTwelve healthy subjects (6 men, 6 women; aged 66–79 y) were studied on 3 separate occasions in a randomized, double-blind, crossover design. After an overnight fast, subjects had concurrent measurements of BP and heart rate (HR; automated device), SMA blood flow (Doppler ultrasound), and blood glucose (glucometer) during intraduodenal infusion of 1) glucose (25% wt:vol, ∼1400 mOsmol/L), 2) sucralose (4 mmol/L, ∼300 mOsmol/L), or 3) saline (0.9% wt:vol, ∼300 mOsmol/L) at a rate of 3 mL/min for 60 min followed by intraduodenal saline for a further 60 min.ResultsThere was a decrease in mean arterial BP (P < 0.001) during intraduodenal glucose [baseline (mean ± SEM): 91.7 ± 2.6 mm Hg compared with t = 60 min: 85.9 ± 2.8 mm Hg] but not during intraduodenal saline or intraduodenal sucralose. The HR (P < 0.0001) and SMA blood flow (P < 0.0001) also increased during intraduodenal glucose but not during intraduodenal saline or intraduodenal sucralose. As expected, blood glucose concentrations increased in response to glucose (P < 0.0001) but not saline or sucralose.ConclusionsIn healthy older subjects, intraduodenal administration of the artificial sweetener sucralose was not associated with changes in BP or SMA blood flow. Further studies are therefore warranted to determine the potential role for artificial sweeteners as a therapy for PPH. This trial was registered at http://www.ANZCTR.org.au as ACTRN12617001249347.

Effects of gastric distension on blood pressure and superior mesenteric artery blood flow responses to intraduodenal glucose in healthy older subjects

2010 ◽  
Vol 299 (3) ◽  
pp. R960-R967 ◽  
Author(s):  
Lora Vanis ◽  
Diana Gentilcore ◽  
Trygve Hausken ◽  
Amelia N. Pilichiewicz ◽  
Kylie Lange ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Random Order ◽  
Gastric Distension ◽  
Mean Velocity ◽  
Intraduodenal Infusion ◽  
Men 2 ◽  
Older Subjects

Postprandial hypotension occurs frequently and is associated with increased morbidity. Gastric distension may attenuate the postprandial fall in blood pressure (BP). Using a barostat, we sought to determine the effects of gastric distension on BP, heart rate (HR), and superior mesenteric artery (SMA) blood flow responses to intraduodenal glucose in eight (6 men, 2 women) healthy older (65–75 yr old) subjects. BP and HR were measured using an automated device and SMA blood flow was measured using Doppler ultrasound on 4 days in random order. SMA blood flow was calculated using the radius of the SMA and time-averaged mean velocity. Subjects were intubated with a nasoduodenal catheter incorporating a duodenal infusion port. On 2 of the 4 days, they were intubated orally with a second catheter, incorporating a barostat bag, positioned in the fundus and set at 8 mmHg above minimal distending pressure. Each subject received a 60-min (0–60 min) intraduodenal infusion of glucose (3 kcal/min) or saline (0.9%); therefore, the four study conditions were as follows: intraduodenal glucose + barostat (glucose + distension), intraduodenal saline + barostat (saline + distension), intraduodenal glucose (glucose), and intraduodenal saline (saline). Systolic and diastolic BP fell during glucose compared with saline ( P = 0.05 and P = 0.003, respectively) and glucose + distension ( P = 0.01 and P = 0.05, respectively) and increased during saline + distension compared with saline ( P = 0.04 and P = 0.006, respectively). The maximum changes in systolic BP were −14 ± 5, +11 ± 2, −3 ± 4, and +15 ± 3 mmHg for glucose, saline, glucose + distension, and saline + distension, respectively. There was an increase in HR during glucose and glucose + distension (maximum rise = 14 ± 2 and 14 ± 3 beats/min, respectively), but not during saline or saline + distension. SMA blood flow increased during glucose and glucose + distension (2,388 ± 365 and 1,673 ± 187 ml/min, respectively), but not during saline, and tended to decrease during saline + distension (821 ± 115 and 864 ± 116 ml/min, respectively). In conclusion, gastric distension has the capacity to abolish the fall in BP and attenuate the rise in SMA blood flow induced by intraduodenal glucose in healthy older subjects.

Effects of Oral Alcohol on Superior Mesenteric Artery Blood Flow in Normal Man, Horizontal and Tilted

1993 ◽  
Vol 84 (4) ◽  
pp. 419-425 ◽  
Author(s):  
S. Maule ◽  
K. Ray Chaudhuri ◽  
T. Thomaides ◽  
D. Pavitt ◽  
J. McCleery ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Body Weight ◽  
Cardiac Index ◽  
Superior Mesenteric Artery ◽  
Mesenteric Artery ◽  
Cardiovascular Effects ◽  
Normal Subjects ◽  
Head Up Tilt

1. The cardiovascular effects of oral alcohol (0.5 g/kg body weight diluted to 300 ml in sugar-free orange juice) were compared with those of placebo in 10 normal subjects. Measurements were made while the subjects were supine and horizontal for 45 min and after 10 min of 45° head-up tilt. 2. After alcohol, plasma alcohol levels rose from 1.9 ± 1.3 to 61.6 ± 6.5 mg/100 ml. After placebo, plasma alcohol levels did not increase. After alcohol and placebo, supine blood pressure was unchanged; heart rate, both supine and during tilt, rose after alcohol only. 3. After alcohol, superior mesenteric artery and digital skin blood flow increased and calculated vascular resistances fell. There was no change after placebo. 4. Forearm blood flow, forearm vascular resistance and cardiac index did not change in either phase, except for a fall in cardiac index during tilt but only after alcohol. 5. In conclusion, the acute ingestion of 0.5 g of alcohol/kg body weight in normal subjects raised heart rate and actively dilated the superior mesenteric artery and digital skin vessels. There was no effect on blood pressure, cardiac output and skeletal muscle vascular tone. During head-up tilt after alcohol, there was a tendency for blood pressure to fall with a compensatory rise in heart rate.

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.

Hypotensive and Regional Haemodynamic Effects of Exercise, Fasted and after Food, in Human Sympathetic Denervation

1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Superior Mesenteric Artery ◽  
Vascular Resistance ◽  
Mesenteric Artery ◽  
Autonomic Failure ◽  
Sympathetic Denervation ◽  
Stroke Distance

1. In human sympathetic denervation due to primary autonomic failure, food and exercise in combination may produce a cumulative blood pressure lowering effect due to simultaneous splanchnic and skeletal muscle dilatation unopposed by corrective cardiovascular reflexes. We studied 12 patients with autonomic failure during and after 9 min of supine exercise, when fasted and after a liquid meal. Standing blood pressure was also measured before and after exercise. 2. When fasted, blood pressure fell during exercise from 162 ± 7/92 ± 4 to 129 ± 9/70 ± 5 mmHg (mean arterial pressure by 22 ± 5%), P < 0.0005. After the meal, blood pressure fell from 159 ± 8/88 ± 6 to 129 ± 6/70 ± 4 mmHg (mean arterial pressure by 22 ± 3%), P < 0.0001, and further during exercise to 123 ± 6/61 ± 3 mmHg (mean arterial pressure by 9 ± 3%), P < 0.01. The stroke distance—heart rate product, an index of cardiac output, did not change after the meal. During exercise, changes in the stroke distance—heart rate product were greater when fasted. 3. Resting forearm and calf vascular resistance were higher when fasted. Calf vascular resistance fell further after exercise when fasted. Resting superior mesenteric artery vascular resistance was lower when fed; 0.19 ± 0.02 compared with 032 ± 0.06, P < 0.05. After exercise, superior mesenteric artery vascular resistance had risen by 82%, to 0.53 ± 0.12, P < 0.05 (fasted) and by 47%, to 0.29 ± 0.05, P < 0.05 (fed). 4. On standing, absolute levels of blood pressure were higher when fasted [83 ± 7/52 ± 7 compared with 71 ± 2/41 ± 3 (fed), each P < 0.05]. Subjects were more symptomatic on standing post-exercise when fed. 5. In human sympathetic denervation, exercise in the fed state lowered blood pressure further than when fasted and worsened symptoms of postural hypotension.

Effect of age on cutaneous vasoconstrictor responses to norepinephrine in humans

2004 ◽  
Vol 287 (5) ◽  
pp. R1230-R1234 ◽  
Author(s):  
Thad E. Wilson ◽  
Kevin D. Monahan ◽  
Daniel S. Short ◽  
Chester A. Ray
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Dose Response ◽  
Laser Doppler ◽  
Vascular Conductance ◽  
Microdialysis Probe ◽  
Arterial Blood ◽  
Older Subjects ◽  
Young Subjects ◽  
Cutaneous Vascular Conductance

To test the hypothesis that cutaneous vasoconstrictor responsiveness to exogenous norepinephrine is reduced in older compared with young subjects, dose-response relations between norepinephrine and skin blood flow were established. Seven doses of norepinephrine (1·10−8 to 10−2 log M) were perfused (2 μl/min) intradermally (4 min/dose) using cutaneous microdialysis (2 probes/subject). To account for possible differences in endogenous norepinephrine between groups, one microdialysis probe was perfused with bretylium tosylate to locally block noradrenergic vesicle release before establishing the norepinephrine dose-response relations. Skin blood flow was indexed via laser-Doppler flowmetry directly over both microdialysis probe sites and is expressed as cutaneous vascular conductance (laser-Doppler flux/mean arterial blood pressure). Local skin temperature was maintained at 34°C at both sites throughout the protocol. Dose-response relation between norepinephrine and cutaneous vascular conductance was similar between control and bretylium-pretreated sites in young subjects (EC50 = −5.18 ± 0.27 and −5.03 ± 0.27 log M, respectively). In contrast, the dose-response relation was significantly shifted to the right (i.e., a higher dose of norepinephrine was needed to produce the same vasoconstrictor response) in the bretylium-pretreated site in older subjects (EC50 = −5.46 ± 0.23 and −4.53 ± 0.23 log M, respectively). Significant increases in EC50 were observed in older compared with young subjects at the bretylium-pretreated but not the control sites. These data indicate that cutaneous vasoconstrictor responsiveness is decreased in older subjects when endogenous release of norepinephrine is antagonized. Furthermore, these findings suggest that differences in presynaptic norepinephrine release between older and younger subjects are profound enough to affect dose-response relations between norepinephrine and cutaneous vascular conductance.

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.

Long-term estrogen deficiency lowers regional blood flow, resting systolic blood pressure, and heart rate in exercising premenopausal women

2007 ◽  
Vol 292 (5) ◽  
pp. E1401-E1409 ◽  
Author(s):  
Emma O'Donnell ◽  
Paula J. Harvey ◽  
Jack M. Goodman ◽  
Mary Jane De Souza
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Vascular Function ◽  
Regional Blood Flow ◽  
Premenopausal Women ◽  
Vascular Conductance ◽  
Menstrual Status

The cardiovascular consequences of hypoestrogenism in premenopausal women are unclear. Accordingly, the influence of menstrual status and endogenous estrogen (E2) exposure on blood pressure (BP), heart rate (HR), and calf blood flow in young (18–35 yr) regularly exercising premenopausal women with exercise-associated menstrual aberrations was investigated. Across consecutive menstrual cycles, daily urinary ovarian steroid levels were analyzed, and the area under the curve was calculated to determine menstrual status and E2exposure. BP, HR, blood flow, vascular conductance, and resistance were measured at baseline and following ischemic calf exercise. Exercising subjects consisted of 14 ovulatory (ExOv), 10 short-term (anovulatory and ≤100 days amenorrhea; ST-E2Def), and 8 long-term (>100 days amenorrhea; LT-E2Def) E2-deficient women. Nine sedentary ovulatory subjects (SedOv) were also studied. All groups were similar in age (24.8 ± 0.7 yr), height (164.8 ± 1.3 cm), weight (57.9 ± 0.9 kg), and body mass index (21.3 ± 0.3 kg/m2). E2-deficient groups had lower ( P < 0.002) E2exposure compared with ovulatory groups. Resting systolic BP, HR, blood flow, and vascular conductance were lower ( P < 0.05) and vascular resistance higher ( P < 0.05) in LT-E2Def compared with both ovulatory groups. Peak ischemic blood flow, vascular conductance, and HR were also lower ( P < 0.05) and vascular resistance higher ( P < 0.05) in LT-E2Def compared with all other groups. Our findings show that exercising women with long-term E2deficiency have impaired regional blood flow and lower systolic BP and HR compared with exercising and sedentary ovulatory women. These cardiovascular alterations represent markers of altered vascular function and autonomic regulation of which the long-term effects remain unknown.

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.

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