The effect of captopril on the superior mesenteric artery and portal venous blood flow in normal man.

Ray‐Chaudhuri, K.; Thomaides, T.; Maule, Simona; Watson, Laura; Lowe, Stephen L.; Mathias, C. J.

doi:10.1111/j.1365-2125.1993.tb04178.x

Cited by 14 publications

(15 citation statements)

References 38 publications

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“…It is thought that the differential increase in sympathetic nervous activity of each organ in the abdomen leads to the different local vascular response in splanchnic organs, and angiotensin (ANG) II is then thought to play a major role in the regulation of splanchnic blood flow during exercise in humans (1,11,26,35,36). However, ANG II may not be the main factor in the regulation of abdominal blood flow because the duration of the cycling exercise in the present study was short and, therefore, it is more likely that blood flow to these organs is sympathetically controlled by the central nervous system (11,16,17,22,29,39).…”

Section: Discussionmentioning

confidence: 99%

Differential arterial blood flow response of splanchnic and renal organs during low-intensity cycling exercise in women

Endo

Suzuki

Nagahata

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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To investigate the regional hemodynamic responses of abdominal arteries at the onset of exercise and to focus on their transient responses, eight female subjects (21-30 yr) performed ergometer cycling exercise at 40 W for 4 min in a semi-supine position. Mean blood velocities (MBVs) in the right renal (RA), superior mesenteric (SMA), and splenic (SA) arteries were measured by pulsed echo-Doppler ultrasonography, with beat-by-beat measurements of heart rate (HR) and mean arterial pressure (MAP). The vascular resistance index (RI) of each artery was calculated from MBV/MAP. MAP (76 +/- 9 to 83 +/- 8 mmHg at 4 min) and HR (60 +/- 7 to 101 +/- 9 beats/min at 4 min) increased during exercise (P < 0.05). The MBV of RA and SA rapidly decreased after the onset of exercise (30 s; -19 +/- 5% and -19 +/- 12%, respectively), reaching -27 +/- 7% and -27 +/- 15% at the end of exercise (P < 0.05). RI did not change during the initial 30 s of exercise, reflecting a reduction in MAP, and increased toward the end of the exercise (+55 +/- 21% and +59 +/- 39%, respectively). In contrast, both the MBV and RI in the SMA remained constant throughout the exercise. The results indicate that, whereas the responses of renal and splenic vessels changed similarly throughout the protocol, the vascular response of SMA that mainly supplies blood to the intestinal tract was unchanged during exercise. We, therefore, conclude that low-intensity cycling exercise resulted in differential blood flow responses in arteries supplying the abdominal organs.

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Section: Discussionmentioning

confidence: 99%

Differential arterial blood flow response of splanchnic and renal organs during low-intensity cycling exercise in women

Endo

Suzuki

Nagahata

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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“…Angiotensin II acting on Ang II type 1 (AT 1 ) receptors also appears continuously to regulate the renal blood flow and vascular resistance of rats with aortocaval fistula shortly after fistula creation (Brodsky et al 1998). However, in healthy humans and those with heart failure, Ang II continuously regulates blood flow through the superior mesenteric artery, but not the renal artery (Ray-Chaudhuri et al 1993;Houghton et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Angiotensin II control of regional haemodynamics in rats with aortocaval fistula

Duggan

Tabrizchi

2016

Experimental Physiology

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New Findings r What is the central question of this study?Hyperdynamic circulation because of arteriovenous fistula results in reduction of blood flow to organs but is a model of low circulatory resistance with activated renin-angiotensin system. The aim was to determine contributions of different subtypes of angiotensin II receptors to regional blood flow and vascular conductance in a hyperdynamic circulatory state. r What is the main finding and its importance?The renin-angiotensin system plays a pivotal role in control of regional blood flow in animals with arteriovenous fistula and makes a major contribution to the maintenance of normal arterial blood pressure. In this hyperdynamic circulatory state model, angiotensin II type 1 receptors predominated in regulating regional haemodynamics.Regional perfusion is reduced and the renin-angiotensin system activated in rats with aortocaval fistula. The effects of captopril (angiotensin-converting enzyme inhibitor), losartan (angiotensin II type 1 receptor antagonist) and PD 123319 (angiotensin II type 2 receptor antagonist) on regional blood flow and vascular conductance were assessed in rats with aortocaval fistula and sham-operated rats. Control of blood flow and vascular conductance by angiotensin II was evaluated by serial bolus injections of captopril, losartan and PD 123319 in anaesthetized rats. In rats with fistula, PD 123319 significantly decreased, whereas captopril and losartan increased, mesenteric blood flow. The decrease in mesenteric blood flow induced by PD 123319 was significantly greater in rats with fistula compared with sham operation. Captopril and PD 123319 significantly decreased renal blood flow compared with losartan, which increased it. In sham-operated rats, captopril and losartan significantly increased, whereas PD 123319 decreased, mesenteric and renal conductance. In rats with fistula, captopril and losartan significantly increased, whereas PD 123319 decreased, mesenteric conductance. The significant increase produced by losartan on mesenteric conductance was greater in rats with fistula compared with sham operation. PD 123319 produced a significantly greater decrease in renal conductance of rats with aortocaval fistula compared with sham-operated rats. Captopril, losartan and PD 123319 did not significantly affect perfusion in the hindquarter in rats with fistula or sham-operated. The renin-angiotensin system is more active in the control of regional haemodynamics in rats with aortocaval fistula and acts as a mechanism of maintaining normal arterial blood pressure in these animals. In rats with fistula, angiotensin II type 1 receptors predominate in regulating regional haemodynamics.

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“…First, ACE-I reduced gastric mHbO 2 . The RAAS is known to reduce mesenteric perfusion (McNeill et al 1977, Bulkley et al 1985, Bailey et al 1986, Reilly et al 1997, and inhibition of the RAAS during captopril therapy increased blood flow in the superior mesenteric artery (Ray-Chaudhuri et al 1993). Similar effects are observed during long-term treatment (Rozsa & Sonkodi 1995) and in critically ill trauma patients (Kincaid et al 1998).…”

Section: Interpretation Of the Resultsmentioning

confidence: 73%

Hypercapnia counteracts captopril-induced depression of gastric mucosal oxygenation

Vollmer

Schwartges

Behmke

et al. 2013

Journal of Endocrinology

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Hypercapnia (HC) increases systemic oxygen delivery (DO 2 ) and gastric mucosal oxygenation. However, it activates the renin-angiotensin-aldosterone system (RAAS), which conversely reduces mesenteric perfusion. The aims of this study were to evaluate the effect of RAAS inhibition during normocapnia and HC on oral and gastric mucosal oxygenation (mHbO 2 ) and to assess the effect of blood pressure under these circumstances. Five dogs were repeatedly anesthetized to study the effects of ACE inhibition (ACE-I; 5 mg/kg captopril, followed by 0.25 mg/kg per h) on mHbO 2 (reflectance spectrophotometry) and hemodynamic variables during normocapnia (end-tidal CO 2 Z35 mmHg) and HC (end-expiratory carbon dioxide (etCO 2 )Z70 mmHg). In the control group, the dogs were subjected to HC alone. To exclude the effects of reduced blood pressure, in one group, blood pressure was maintained at baseline values via titrated phenylephrine (PHE) infusion during HC and additional captopril infusion. ACE-I strongly reduced gastric mHbO 2 from 72G2 to 65G2% and mean arterial pressure (MAP) from 64G2 to 48G4 mmHg, while DO 2 remained unchanged. This effect was counteracted in the presence of HC, which increased gastric mHbO 2 from 73G3 to 79G6% and DO 2 from 15G2 to 22G4 ml/kg per min during ACE-I without differences during HC alone. However, MAP decreased similar to that observed during ACE-I alone from 66G3 to 47G5 mmHg, while left ventricular contractility (dP max ) increased from 492G63 to 758G119 mmHg/s. Titrated infusion of PHE had no additional effects on mHbO 2 . In summary, our data suggest that RAAS inhibition reduces gastric mucosal oxygenation in healthy dogs. HC not only abolishes this effect, but also increases mHbO 2 , DO 2 , and dP max . The increase in mHbO 2 during ACE-I under HC is in accordance with our results independent of blood pressure.

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The effect of captopril on the superior mesenteric artery and portal venous blood flow in normal man.

Cited by 14 publications

References 38 publications

Differential arterial blood flow response of splanchnic and renal organs during low-intensity cycling exercise in women

Differential arterial blood flow response of splanchnic and renal organs during low-intensity cycling exercise in women

Angiotensin II control of regional haemodynamics in rats with aortocaval fistula

Hypercapnia counteracts captopril-induced depression of gastric mucosal oxygenation

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