The importance of the spleen in blood volume shifts of the systemic vascular bed caused by the carotid sinus baroreceptor reflex in the dog.

Shoukas, Artin A.; MacAnespie, C. L.; Brunner, M. J.; Watermeier, L

doi:10.1161/01.res.49.3.759

Cited by 28 publications

(11 citation statements)

References 15 publications

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“…The changes in systemic variables are consistent with our previous findings (Schmidt et al, 1971;Shoukas and Sagawa, 1973;Drees and Rothe, 1974;Numao, 1977;Shoukas et al, 1980;Shoukas et al, 1981). In addition, the pulmonary compliance values I obtained in this series of experiments (0.30 ml/mm Hg per kg at intrasinus pressure of 50 mm Hg and 0.33 ml/mm Hg per kg intrasinus pressure of 200 mm Hg) are consistent with the sum of the arterial and venous compliances that I reported previously using an entirely different technique (Shoukas, 1975).…”

Section: Discussionsupporting

confidence: 91%

“…1 decreased while the venous pressure increased and reached a steady state value after 2-3 minutes. This change in steady state volume, corrected for filtration (Shoukas et a!., 1981), divided by the change in steady state venous pressure, is the total systemic vascular compliance. The height of the outflow then was lowered to its previous control level of 5 mm Hg, which then caused a concomitant increase in steady state reservoir volume.…”

Section: Surgical Preparationmentioning

confidence: 99%

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Carotid sinus baroreceptor reflex control and epinephrine. Influence on capacitive and resistive properties of the total pulmonary vascular bed of the dog.

Shoukas¹

1982

Circulation Research

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To quantify the importance of the carotid sinus baroreceptor reflex and the interaction with epinephrine infusion on total pulmonary vascular capacity and resistance, I have simultaneously measured total pulmonary vascular compliance, changes in pulmonary blood volumes, and changes in resistances in seven sodium pentobarbital-anesthetized dogs. A preparation was used that bypasses the right and left hearts allowing for the simultaneous measurement of the pulmonary as well as the systemic vascular bed parameters. At intrasinus pressures of 50, 125, and 200 mm Hg, without epinephrine infusion, the pulmonary vascular resistance was 0.134, 0.121, and 0.109 mm Hg/(ml per min per kg) and the systemic vascular resistance was 1.21, 0.87, and 0.63 mm Hg/(ml per min per kg). Epinephrine infusion of 1 microgram/min per kg at each intrasinus pressure caused the resistances of both vascular beds to increase. Pulmonary vascular resistance increased to 0.157 mm Hg/(ml per min per kg) and showed no further changes with changes in ISP. However, systemic vascular resistance did decrease from 1.49 to 1.41 and 1.25 at intrasinus pressures of 50, 125, and 200 mm Hg. During control runs, pulmonary vascular capacity changed 1.06 ml/kg and systemic capacity changed 7.63 ml/kg for SP changes between 50 and 200 mm Hg. Both responses were greatly attenuated after epinephrine infusion and amounted to only 0.17 ml/kg for the pulmonary and vascular bed and 2.26 ml/kg for the systemic vascular bed. The differences in capacity changes between control and epinephrine runs for the two vascular beds were nearly equal to the change in capacities brought about by epinephrine when it was infused at a fixed intrasinus pressure of 125 mm Hg. The pulmonary vascular compliance during the control runs increased from 0.303 to 0.329 ml/mm Hg per kg when ISP was increased from 50 to 200 mm Hg. After epinephrine infusion, the pulmonary compliance was 0.273 ml/mm Hg per kg and showed no changes with intrasinus pressure. Similar results were obtained for the systemic vascular compliance which was 2.07 ml/mm Hg per kg at an ISP of 50 mm Hg and increased to 2.39 ml/mm Hg per kg to an ISP of 200 mm Hg during control runs. After epinephrine infusion, the systemic compliance was 1.89 ml/mm Hg per kg and again showed no changes with ISP. These data indicate that the baroreceptor reflex can exert control of pulmonary and systemic vascular resistance and capacitance and epinephrine can greatly attenuate the reflex control of both vascular beds.

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Section: Discussionsupporting

confidence: 91%

Section: Surgical Preparationmentioning

confidence: 99%

Carotid sinus baroreceptor reflex control and epinephrine. Influence on capacitive and resistive properties of the total pulmonary vascular bed of the dog.

Shoukas¹

1982

Circulation Research

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“…Splanchnic filling during HUT differs from findings during hemorrhage in which splanchnic emptying occurs and may comprise up to 65% of the total volume of blood lost during the hemorrhage (17). Vatner (42), observing the central reservoir function of the splanchnic vasculature, noted that small increases in splanchnic arterial resistance sustained cardiac output during mild nonhypotensive hemorrhage, whereas others observed that incrementally severe hemorrhage produced almost complete splanchnic emptying (5,37) by the rapid mobilization of venous blood in response to baroreceptor unloading (18,32).…”

mentioning

confidence: 99%

Differential effects of lower body negative pressure and upright tilt on splanchnic blood volume

Taneja¹,

Moran²,

Medow³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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Taneja I, Moran C, Medow MS, Glover JL, Montgomery LD, Stewart JM. Differential effects of lower body negative pressure and upright tilt on splanchnic blood volume. Am J Physiol Heart Circ Physiol 292: H1420 -H1426, 2007. First published November 3, 2006; doi:10.1152/ajpheart.01096.2006.-Upright posture and lower body negative pressure (LBNP) both induce reductions in central blood volume. However, regional circulatory responses to postural changes and LBNP may differ. Therefore, we studied regional blood flow and blood volume changes in 10 healthy subjects undergoing graded lower-body negative pressure (Ϫ10 to Ϫ50 mmHg) and 8 subjects undergoing incremental head-up tilt (HUT; 20°, 40°, and 70°) on separate days. We continuously measured blood pressure (BP), heart rate, and regional blood volumes and blood flows in the thoracic, splanchnic, pelvic, and leg segments by impedance plethysmography and calculated regional arterial resistances. Neither LBNP nor HUT altered systolic BP, whereas pulse pressure decreased significantly. Blood flow decreased in all segments, whereas peripheral resistances uniformly and significantly increased with both HUT and LBNP. Thoracic volume decreased while pelvic and leg volumes increased with HUT and LBNP. However, splanchnic volume changes were directionally opposite with stepwise decreases in splanchnic volume with LBNP and stepwise increases in splanchnic volume during HUT. Splanchnic emptying in LBNP models regional vascular changes during hemorrhage. Splanchnic filling may limit the ability of the splanchnic bed to respond to thoracic hypovolemia during upright posture.vasoconstriction; splanchnic; blood volume; orthostatic stress; hemorrhage STANDING TRANSLOCATES BLOOD from the central thoracic circulation to the dependent regional circulations, producing ϳ20% reduction in cardiac output. The decrease in cardiac output comprises a 40% decrease in stroke volume associated with reflex tachycardia, increased peripheral resistance, and a generally maintained systolic blood pressure (SBP) with somewhat reduced pulse pressure (PP) while quietly standing (35). Changes in circulatory physiology during head-up tilt (HUT) are said to resemble the changes observed during hypovolemia caused by dehydration or hemorrhage (39, 41).Lower body negative pressure (LBNP; see Refs. 44 -46) has been used as a reversible simulation for hemorrhage (8,30). LBNP has also been used to model orthostatic stress (7) because many of the changes of neurovascular physiology resemble changes during standing or HUT (31). Thus, for example, both HUT and LBNP produce central hypovolemia and comparable unloading of the cardiopulmonary and arterial baroreceptors (9, 19). However, gravitational differences in regional vascular properties have also been noted (21, 24). Thus recent work by Cooke et al. (8) and el Bedawi and Hainsworth (12) has demonstrated that, although LBNP physiology most closely resembles the physiology of acute hemorrhage, it may be incomplete as a model for orthostatic stress, which must prod...

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“…), CPL, or both (Shoukas et al. ; Monahan and Ray ), which could assist the shift of blood from veins to the heart and maintain central blood volume and blood pressure (Rothe ).…”

Section: Introductionmentioning

confidence: 99%

“…The veins have high compliance (CPL), so the venous component of the cardiovascular system plays an important role as a blood reservoir, containing approximately 70% of the total blood volume at rest. Physiologic stressors, such as exercise, orthostatic stress, and exposure to heat, change venous capacitance (Drees and Rothe 1974;Greenway et al 1985), CPL, or both (Shoukas et al 1981;Monahan and Ray 2004), which could assist the shift of blood from veins to the heart and maintain central blood volume and blood pressure (Rothe 1983).…”

Section: Introductionmentioning

confidence: 99%

Compliance in the deep and superficial conduit veins of the nonexercising arm is unaffected by short-term exercise

Oue

Sadamoto

2018

Physiol Rep

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The effects of short‐term dynamic and static exercise on compliance (CPL) in a single conduit vein in the nonexercising limb are not fully understood, although prolonged cycling exercise was found to produce a significant reduction of CPL in the veins. In this study, we investigated the cross‐sectional area (CSA) and CPL in the brachial (deep) and basilic (superficial) veins of the nonexercising arm in 14 participants who performed a 5‐min cycling exercise at 35% and 70% of peak oxygen uptake (study 1) and in 11 participants who performed a 2‐min static handgrip exercise at 30% of maximal voluntary contraction (study 2). The CSA in the deep and superficial veins at rest and during the final minute of exercise was measured by high‐resolution ultrasonography during a short‐duration cuff deflation protocol. The CPL in each vein was calculated as the numerical derivative of the cuff pressure and CSA curve. During short‐term dynamic and static exercise, there was no change in CPL in either vein, but there was a decrease in CSA in both veins. The simultaneous findings of unchanged CPL and decreased CSA suggest that CPL during short‐term exercise are independently controlled by the mechanisms responsible for exercise‐induced sympathoexcitation in both single veins. Thus, short‐term exercise does not alter CPL in both conduit superficial and deep veins in nonexercising upper arm.

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The importance of the spleen in blood volume shifts of the systemic vascular bed caused by the carotid sinus baroreceptor reflex in the dog.

Cited by 28 publications

References 15 publications

Carotid sinus baroreceptor reflex control and epinephrine. Influence on capacitive and resistive properties of the total pulmonary vascular bed of the dog.

Carotid sinus baroreceptor reflex control and epinephrine. Influence on capacitive and resistive properties of the total pulmonary vascular bed of the dog.

Differential effects of lower body negative pressure and upright tilt on splanchnic blood volume

Compliance in the deep and superficial conduit veins of the nonexercising arm is unaffected by short-term exercise

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