Changes in Small Vessel Blood Content of the Rat Heart Induced by Hypercapnic, Hyperoxic or Asphyxic Conditions

Weiss, Harvey R.; Cohen, Jay A.

doi:10.1159/000169898

Cited by 7 publications

(2 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8 -"- 28 Nevertheless, these results do not necessarily contradict those observations reported above if one defines capillary recruitment as the fraction of capillaries perfused at a given point in time. If flow and stagnation frequently change within the microvascular system, rapid shifts in this pattern would change the surface area available for exchange even if the number of capillaries open to flow remains constant.…”

Section: Discussionmentioning

confidence: 60%

Hypoxia-induced acute changes in capillary and fiber density and capillary red cell distribution in the rat heart.

Vetterlein¹,

Hemeling²,

Sammler³

et al. 1989

Circulation Research

View full text Add to dashboard Cite

The influence of acute hypoxia (respiration gas 12%, 10%, and 8% O 2 and asphyxia, respectively) on 1) the density of perfused capillaries and muscle fibers, and 2) the capillary red cell distribution was investigated in the left heart of anesthetized rats. To observe capillaries and fibers, fluorescein isothiocyanate-labeled (FITC)-y-globulin and lissamine-rhodamine-B200-labeled (RB200) myoglobin were injected intravenously as labels of the perfused intravasal and the extracellular space, respectively. The hypoxic conditions were induced subsequently and maintained for 3 minutes. After this period the heart was rapidly frozen for histological demonstration of the dyes. Ventilation with 12% or 10% O 2 did not induce any changes in the density of perfused capillaries; however, 8% O 2 in respiration gas did lead to a significant increase (capillaries/nun 2 : subepicardium, 4,180, controls, 3,620; subendocardium, 3,930, controls, 3,240). A similar increase was found in the asphyxia group (capillaries/mm 2 : subepicardium, 4,170; subendocardium, 3,700). The increases in the density of perfused capillaries were paralleled by rises in fiber density. This leads to the conclusion that the changes in capillary counts were caused by fiber elongation with a resultant decrease in intercapillary distances. This assumption was supported by observations that there were no signs of changes in ventricular segment length during respiration of 12% or 10% O 2 but that an increase did occur with 8% oxygen and with asphyxia. Densities of perfused capillaries exactly coincided with anatomical densities (demonstrated by additional labeling of capillary basement membranes with isolectin B 4 ) in normoxic and asphyctic hearts. The distribution of red cells in the capillaries, determined in histological sections, did not differ appreciably under hypoxia due to reduced O 2 in respiration air (12%) or asphyxia. The results obtained indicate that 1) extreme hypoxic states cause the capillaries to move closer to each other due to elongation of myocardial fibers and 2) red cell distribution is not altered during these conditions. (Circulation Research 1989;64:742-752)

show abstract

Section: Discussionmentioning

confidence: 60%

Hypoxia-induced acute changes in capillary and fiber density and capillary red cell distribution in the rat heart.

Vetterlein¹,

Hemeling²,

Sammler³

et al. 1989

Circulation Research

View full text Add to dashboard Cite

show abstract

“…A species difference between the canine and rat hearts has also been reported. The blood volume in the regional small blood vessels of the rat myocardium appears to be relative ly uniform throughout the heart while in dogs, there arc gradients in small vessel blood content between the differ ent ventricular walls, from base to apex and between superficial and deep layers of the same wall [21][22][23].…”

Section: Discussionmentioning

confidence: 97%

Microvascular Permeability of the Isolated Rat Heart to Various Solutes in Well-Oxygenated and Hypoxic Conditions

Al-Haboubi¹,

Ward²

1996

Int J Microcirc

View full text Add to dashboard Cite

The aim of this study was to investigate the effect of a moderate degree of hypoxia on coronary vascular permeability to various lipophobic solutes. Using the multiple indicator dilution method the permeability-surface area (PS) products were determined for ¹²⁵I-albumin, ¹²⁵I-insulin and ⁵⁷Co-cyanocobalamin in perfused rat hearts (flow ≈10 ml·min^-1 •g^-1) either with well-oxygenated (pO₂ ≈ 96 kPa) or hypoxic (pO₂ ≈ 45 kPa) solutions. The PS products for albumin, insulin and cyanocobalamin during the well-oxygenated equilibration period were 0.20 ± 0.03, 0.29 ± 0.06 and 2.0 ± 0.3 ml·min^-1.g^-1 (mean ± SE), respectively, relative to ¹³¹I-n-globulin. The PS products for these solutes 15 min after the induction of hypoxia were 1.3 ± 0.3,0.8 ± 0.1 (p < 0.05) and 2.1 ± 0.2 (p > 0.05), respectively. In hearts perfused with well-oxygenated solution for 75 min, the PS products for these solutes remained stable throughout the period of the study. Electron-microscopic examination of hypoxic tissues showed the presence of endothelial gaps of approximately 1 µm which were underlined by an intact basal lamina. We conclude that a moderate degree of hypoxia produces a large increase in permeability of albumin and insulin but has no effect on the PS products for cyanocobalamin and that the endothelial gaps are the likely mechanism of the observed increase in permeability.

show abstract

Microcirculation in the Stressed Heart

Rakusan¹

1987

Developments in Cardiovascular Medicine

View full text Add to dashboard Cite

Changes in Small Vessel Blood Content of the Rat Heart Induced by Hypercapnic, Hyperoxic or Asphyxic Conditions

Cited by 7 publications

References 18 publications

Hypoxia-induced acute changes in capillary and fiber density and capillary red cell distribution in the rat heart.

Hypoxia-induced acute changes in capillary and fiber density and capillary red cell distribution in the rat heart.

Microvascular Permeability of the Isolated Rat Heart to Various Solutes in Well-Oxygenated and Hypoxic Conditions

Microcirculation in the Stressed Heart

Contact Info

Product

Resources

About