Observations upon the size of the spleen

Barcroft, Joseph; Stephens, J. G.

doi:10.1113/jphysiol.1927.sp002414

Cited by 130 publications

(51 citation statements)

References 3 publications

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“…2326 The arterial concentrations of epinephrine and norepinephrine increased during exercise, as previously described for the dog by PeYonnet et al 27 and Chilian et al 8 Splenic contraction is a normal component of the exercise response in dogs and results in an increased hematocrit. 28 " 30 Because increases in hematocrit make the inner/outer flow ratio more sensitive to stress, 31 splenectomy was performed in each dog in the present study, and hematocrit never increased by more than 1 % during the experimental protocol.…”

Section: Figure 8 Inner! Outer Flow Ratio Vs Myocardial Oxygen Consmentioning

confidence: 99%

Adrenergic coronary vasoconstriction helps maintain uniform transmural blood flow distribution during exercise.

Huang

Feigl

1988

Circulation Research

101

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The hypothesis that a-adrenergic coronary vasoconstriction helps maintain a uniform transmural distribution of myocardial blood flow during exercise was tested in dogs. Carotid artery loops were surgically constructed and a splenectomy performed three weeks prior to study. On the day of study, the dog was anesthetized briefly (fentanyl and nitrous oxide) for percutaneous catheterization, and a-receptors in one myocardial region were blocked with phenoxybenzamine (0.25 mg/kg) infused selectively into the left circumflex coronary artery. Recirculation of phenoxybenzamine was minimized by drainage of coronary sinus outflow during the infusion. After the dog recovered from the anesthesia, regional blood flow was measured at rest and during graded treadmill exercise with the microsphere technique calibrated by reference blood samples. Average transmural flow was limited by avasoconstriction and was less in the region where a-receptors were intact than in the region where they were blocked, as has been described by others. The ratio of inner layer myocardial blood flow to outer layer flow was better maintained in the region with a-receptors intact than in the region with a-receptors blocked when myocardial oxygen consumption was 150 /tl/min/g or greater (p<0.001). Even though average transmural flow was limited by a-receptor activation, inner layer myocardial blood flow was greater in the region with a-receptors intact than in the region with a-receptors blocked when myocardial oxygen consumption was 500 fxVm\n/g or more (p<0.05). In conclusion, adrenergic coronary vasoconstriction mediated by a-receptors helps to maintain a uniform transmural distribution of myocardial blood flow during exercise in spite of limiting average transmural flow. (Circulation Research 1988;62:286-298) W hen the coronary vessels are dilated pharmacologically with adenosine and the heart is electrically paced from 100 to 250 beats/ min, the ratio of inner myocardial blood flow to outer myocardial blood flow (inner/outer flow ratio) falls dramatically from 1.0 to 0.4.' This is consistent with the concept that myocardial compression impedes blood flow to the inner layers of the myocardium more than it does to the outer layers. Because a larger proportion of each cardiac cycle is spent in systole as heart rate increases, tachycardia tends to exaggerate the effects of this transmural gradient of compression.In contrast to the situation with adenosine and pacing, when coronary vasodilation and tachycardia develop in response to exercise, the transmural distribution of coronary blood flow changes little, and the inner/outer flow ratio remains at or above l.O. Received February 10, 1987; accepted August 7, 1987. ergic coronary vasoconstriction mediated by a-receptors is part of the physiological response to exercise. 5 " 9The resulting restriction of functional hyperemia seems paradoxical because the metabolic demand for myocardial blood flow is greatly elevated during exercise. However, the adrenergic vasoconstriction during exercise might i...

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Section: Figure 8 Inner! Outer Flow Ratio Vs Myocardial Oxygen Consmentioning

confidence: 99%

Adrenergic coronary vasoconstriction helps maintain uniform transmural blood flow distribution during exercise.

Huang

Feigl

1988

Circulation Research

101

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“…In some mammals such as dogs and horses, the spleen serves a storage function to hold erythrocytes. In classic experiments with dogs, exercise induced contraction of the spleen to about one-half to one-third of its resting size (65). The rainbow trout spleen also has been reported to have a reservoir function, and it is likely that our sampling procedures induced reservoir erythrocyte release from the spleen (66).…”

Section: How Is Spleen Size Linked To Disease Resistance?mentioning

confidence: 99%

Spleen Size Predicts Resistance of Rainbow Trout to Flavobacterium psychrophilum Challenge

Hadidi

Glenney

Welch

et al. 2008

The Journal of Immunology

149

119

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Selective breeding of animals for increased innate resistance offers an attractive strategy to control disease in agriculture. However, this approach is limited by an incomplete knowledge of the heritability, duration, and mechanism(s) of resistance, as well as the impact of selection on the immune response to unrelated pathogens. Herein, as part of a rainbow trout broodstock improvement program, we evaluated factors involved in resistance against a bacterial disease agent, Flavobacterium psychrophilum. In 2005, 71 full-sibling crosses, weighing an average of 2.4 g, were screened, and resistant and susceptible crosses were identified. Naive cohorts were evaluated at 10 and 800 g in size, and most maintained their original relative resistant or susceptible phenotypes, indicating that these traits were stable as size increased >300-fold. During the course of these studies, we observed that the normalized spleen weights of the resistant fish crosses were greater than those of the susceptible fish crosses. To test for direct association, we determined the spleen-somatic index of 103 fish crosses; created high, medium, and low spleen-index groups; and determined survival following challenge with F. psychrophilum or Yersinia ruckeri. Consistent with our previous observations, trout with larger spleen indices were significantly more resistant to F. psychrophilum challenge; however, this result was pathogen-specific, as there was no correlation of spleen size with survival following Y. ruckeri challenge. To our knowledge, this is the first report of a positive association between spleen size and disease resistance in a teleost fish. Further evaluation of spleen index as an indirect measure of disease resistance is warranted.

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“…There is some evidence to indicate that the moderate increase in cell volume during exhaustive exercise may be due to the addition of red cells from the blood reservoirs to the circulation. In animals there is ample proof that exercise causes the spleen to contract and discharge cells into the blood stream (3). It has been shown that this contraction is mediated through the nervous system and that either lack of oxygen or an increased secretion of adrenin may act as the stimulus.…”

Section: Resultsmentioning

confidence: 99%

The effect of exercise on the volume of the blood

1940

American Heart Journal

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Observations upon the size of the spleen

Cited by 130 publications

References 3 publications

Adrenergic coronary vasoconstriction helps maintain uniform transmural blood flow distribution during exercise.

Adrenergic coronary vasoconstriction helps maintain uniform transmural blood flow distribution during exercise.

Spleen Size Predicts Resistance of Rainbow Trout to Flavobacterium psychrophilum Challenge

The effect of exercise on the volume of the blood

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