Vasoconstrictor role for vasopressin in conscious, sodium-depleted rats

To define the role of vasopressin as a vasoconstrictor hormone in sodium depletion, systemic hemodynamics and regional blood flow distribution were examined in conscious Sprague-Dawley rats after 6 days of a low-sodium diet. Studies were performed after selective or combined blockade with the vasopressin antagonist [d(CH2)5Tyr(Me)]AVP (AVPA), enalaprilat (CEI), and phentolamine (PHENTOL). Plasma levels of vasopressin were increased significantly after CEI and increased further after PHENTOL and CEI plus PHENTOL. AVPA had no effect on blood pressure, whether given alone or in the presence of PHENTOL, CEI, or CEI plus PHENTOL. Significant falls in peripheral vascular resistance associated with reflex increases in cardiac output were observed when AVPA was given to animals pretreated with either CEI or PHENTOL but not both. AVPA alone produced no significant changes in regional blood flow distribution, but a vasoconstrictor action of vasopressin in the renal vascular bed was revealed after prior treatment with CEI or PHENTOL. Muscle blood flow was also increased in the PHENTOL plus AVPA group compared with the PHENTOL group. No significant additional effects of AVPA were revealed by pretreatment with CEI, PHENTOL, or CEI plus PHENTOL for mesenteric, hepatic, splenic, or cerebral vascular beds. It is suggested that vasopressin acts as a vasoconstrictor hormone in conscious sodium-depleted rats when either the renin-angiotensin system or alpha-adrenergic system is inhibited but not when both systems are blocked. The renal vascular bed is an important site for vasopressin-induced vasoconstriction under these circumstances.

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Oxygen consumption and distribution of blood flow in rats climbing a laddermill

Journal of Applied Physiology ◽

10.1152/jappl.1990.68.1.241 ◽

1990 ◽

Vol 68 (1) ◽

pp. 241-247 ◽

Cited By ~ 6

Author(s):

K. I. Norton ◽

M. T. Jones ◽

R. B. Armstrong

Keyword(s):

Blood Flow ◽

Fiber Type ◽

Muscle Blood Flow ◽

Flow Distribution ◽

Treadmill Running ◽

Blood Flow Distribution ◽

Sprague Dawley ◽

Circulatory Response ◽

Blood Flows ◽

Sprague Dawley Rats

The purpose of this study was threefold: 1) to determine whether untrained rats that refused to run on treadmill would climb on a laddermill (75 degrees incline); 2) to determine O2 consumption (VO2) in untrained rats as a function of laddermill climbing speed; and 3) to determine whether the circulatory response of untrained rats to laddermill climbing is similar to that previously reported for treadmill running at an equivalent VO2. Eighteen female Sprague-Dawley rats that would not perform on a treadmill as part of another study were used to measure VO2 as a function of laddermill speed (5-17 m/min). Data were obtained from all 18 rats; VO2 increased linearly as a function of laddermill speed (r = 0.83, y = 3.0 x + 63.2). Twenty-four female Sprague-Dawley rats that also refused to run on a treadmill were used to measure mean arterial pressure, heart rate, and blood flow distribution (with microspheres) during climbing at 5 and 10 m/min. These exercise intensities were metabolically equivalent to level treadmill running at 45 and 60 m/min (VO2 approximately 78 and 93 ml.min-1.kg-1, respectively). Of the 24 animals, 23 were willing to climb. Mean arterial pressures were higher (approximately 10%) during laddermill climbing than during equivalent treadmill running, but heart rates were the same. General blood flow distribution among muscles as a function of fiber type (with red muscles receiving higher flows) and between muscles and visceral tissues (muscle blood flow increased as a function of exercise intensity while visceral blood flows decreased) were similar to data for rats running on the level.(ABSTRACT TRUNCATED AT 250 WORDS)

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Blood flow distribution in working in situ canine muscle during blood flow reduction

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.6.1978 ◽

1996 ◽

Vol 80 (6) ◽

pp. 1978-1983 ◽

Cited By ~ 8

Author(s):

S. S. Kurdak ◽

B. Grassi ◽

P. D. Wagner ◽

M. C. Hogan

Keyword(s):

Blood Flow ◽

Muscle Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Strong Negative Correlation ◽

Flow Heterogeneity ◽

Blood Flow Reduction ◽

Blood Flow Heterogeneity

The purpose of this study was to determine whether reduction in apparent muscle O2 diffusing capacity (Dmo2) calculated during reduced blood flow conditions in maximally working muscle is a reflection of alterations in blood flow distribution. Isolated dog gastrocnemius muscle (n = 6) was stimulated for 3 min to achieve peak O2 uptake (VO2) at two levels of blood flow (controlled by pump perfusion): control (C) conditions at normal perfusion pressure (blood flow = 111 +/- 10 ml.100 g-1.min-1) and reduced blood flow treatment [ischemia (I); 52 +/- 6 ml.100 g-1.min-1]. In addition, maximal vasodilation was achieved by adenosine (A) infusion (10(-2)M) at both levels of blood flow, so that each muscle was subjected randomly to a total of four conditions (C, CA, I, and IA; each separated by 45 min of rest). Muscle blood flow distribution was measured with 15-microns-diameter colored microspheres. A numerical integration technique was used to calculate Dmo2 for each treatment with use of a model that calculates O2 loss along a capillary on the basis of Fick's law of diffusion. Peak VO2 was reduced significantly (P < 0.01) with ischemia and was unchanged by adenosine infusion at either flow rate (10.6 +/- 0.9, 9.7 +/- 1.0, 6.7 +/- 0.2, and 5.9 +/- 0.8 ml.100 g-1.min-1 for C, CA, I, and IA, respectively). Dmo2 was significantly lower by 30-35% (P < 0.01) when flow was reduced (except for CA vs. I; 0.23 +/- 0.03, 0.20 +/- 0.02, 0.16 +/- 0.01, and 0.13 +/- 0.01 ml.100 g-1.min-1.Torr-1 for C, CA, I, and IA, respectively). As expressed by the coefficient of variation (0.45 +/- 0.04, 0.47 +/- 0.04, 0.55 +/- 0.03, and 0.53 +/- 0.04 for C, CA, I, and IA, respectively), blood flow heterogeneity per se was not significantly different among the four conditions when examined by analysis of variance. However, there was a strong negative correlation (r = 0.89, P < 0.05) between Dmo2 and blood flow heterogeneity among the four conditions, suggesting that blood flow redistribution (likely a result of a decrease in the number of perfused capillaries) becomes an increasingly important factor in the determination of Dmo2 as blood flow is diminished.

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Effects of Dopamine and Dobutamine on Regional Blood Flow Distribution in the Neonatal Piglet

Annals of Surgery ◽

10.1097/00000658-199505000-00011 ◽

1995 ◽

Vol 221 (5) ◽

pp. 531-542 ◽

Cited By ~ 26

Author(s):

John J. Ferrara ◽

D. Lynn Dyess ◽

Guy L. Peeples ◽

D. Paul Christenberry ◽

W. Scott Roberts ◽

...

Keyword(s):

Blood Flow ◽

Regional Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Neonatal Piglet

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Muscular blood flow distribution patterns as a function of running speed in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1982.243.2.h296 ◽

1982 ◽

Vol 243 (2) ◽

pp. H296-H306 ◽

Cited By ~ 99

Author(s):

M. H. Laughlin ◽

R. B. Armstrong

Keyword(s):

Blood Flow ◽

Muscle Blood Flow ◽

Flow Distribution ◽

Distribution Patterns ◽

Left Renal Artery ◽

Sprague Dawley ◽

Vastus Intermedius ◽

Slow Twitch ◽

The Right ◽

White Gastrocnemius

Muscle blood flow (BF) was measured using the radiolabeled microsphere technique within and among nine major muscles of rats before exercise and during treadmill walking or running at speeds of 15, 30, 45, 60, and 75 m/min. Measurements were made during exercise after 1 min of steady walking or running. Male Sprague-Dawley rats were chronically instrumented with 2 Silastic catheters, one in the ascending aorta via the right carotid artery for microsphere infusion and one in the left renal artery for arterial reference blood sample withdrawal. The preexercise results demonstrated that 1) BF to deep slow-twitch muscles was three to four times that to peripheral fast muscles (e.g., soleus and gastrocnemius BFs were 138 and 33 ml . min-1 . 100 g-1, respectively); 2) BFs to red portions within mixed muscles were three to four times those to white portions (e.g, red and white gastrocnemius BFs were 54 and 18 ml . min-1 . 100 g-1, respectively; and 3) there was a direct relationship (P less than 0.05) between BFs to muscles and their slow-twitch oxidative fiber populations. The results obtained during exercise demonstrated that 1) at the slowest speed studied (15 m/min) BFs to the red portions of muscles increased, whereas BFs to the white portions of the same muscles decreased; 2) BFs to all muscles (except soleus) were increased during running at 75 m/min when there was a range of flows of 30 ml . 100 g-1 . min-1 (white gastrocnemius) to 321 (vastus intermedius), 3) at all running speeds the increases in BF to muscles were directly related to the fast-twitch, high-oxidative fiber populations of the muscles; and 4) BFs to visceral tissues and fat were decreased during exercise.

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Modeling of Oxygen Transport to Skeletal Muscle: Blood Flow Distribution, Shunt, and Diffusion

Advances in Experimental Medicine and Biology - Oxygen Transport to Tissue XIII ◽

10.1007/978-1-4615-3404-4_1 ◽

1992 ◽

pp. 3-10 ◽

Cited By ~ 5

Author(s):

Johannes Piiper

Keyword(s):

Skeletal Muscle ◽

Blood Flow ◽

Oxygen Transport ◽

Muscle Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Skeletal Muscle Blood Flow ◽

And Diffusion

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Influence of Gravity on Radiographic Contrast Material–Based Measurements of Regional Blood Flow Distribution

Academic Radiology ◽

10.1016/s1076-6332(03)80036-3 ◽

2003 ◽

Vol 10 (2) ◽

pp. 128-138 ◽

Cited By ~ 8

Author(s):

Anne V Clough ◽

Steven T Haworth ◽

David L Roerig ◽

Eric A Hoffman ◽

Christopher A Dawson

Keyword(s):

Blood Flow ◽

Regional Blood Flow ◽

Contrast Material ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Radiographic Contrast ◽

Radiographic Contrast Material

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Regional blood flow distribution during extracorporeal membrane oxygenation in rabbits

Journal of Thoracic and Cardiovascular Surgery ◽

10.1016/s0022-5223(19)34331-4 ◽

1989 ◽

Vol 98 (6) ◽

pp. 1138-1143 ◽

Cited By ~ 24

Author(s):

Todd T. Nowlen ◽

Steven O. Salley ◽

Grant C. Whittlesey ◽

Sourav K. Kundu ◽

Nancy A. Maniaci ◽

...

Keyword(s):

Blood Flow ◽

Extracorporeal Membrane Oxygenation ◽

Regional Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Membrane Oxygenation

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Systemic and Regional Blood Flow Distribution in Unanesthetized Swine and Swine Anesthetized with Halothane + Nitrous Oxide, Halothane, or Enflurane

Survey of Anesthesiology ◽

10.1097/00132586-198302000-00005 ◽

1983 ◽

Vol 27 (1) ◽

pp. 4???5

Author(s):

W. J. TRANQUILLI ◽

M. MANOHAR ◽

C. M. PARKS ◽

J. C. THURMON ◽

M. C. THEODORAKIS ◽

...

Keyword(s):

Blood Flow ◽

Nitrous Oxide ◽

Regional Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution

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Regional blood flow distribution during the Cushing response: alterations with adrenergic blockade

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1985.248.1.h98 ◽

1985 ◽

Vol 248 (1) ◽

pp. H98-H108

Author(s):

D. G. van Wylen ◽

L. G. D'Alecy

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Regional Blood Flow ◽

Flow Distribution ◽

Peripheral Tissue ◽

Systemic Hypertension ◽

Tissue Blood Flow ◽

Blood Flow Distribution ◽

Beta Receptor ◽

Cushing Response

Regional blood flow distribution (microspheres) and cardiac output (CO, thermal dilution) were measured during the Cushing response in unblocked (UB), beta-receptor-blocked (BB, 2 mg/kg propranolol iv), or alpha-receptor blocked (AB, 0.5 mg/kg + 0.5 mg X kg-1 X min-1 phentolamine iv) chloralose-anesthetized dogs. Intracranial pressure was increased to 150 mmHg by infusion of temperature-controlled artificial cerebrospinal fluid into the cisterna magna. Similar increases in mean arterial pressure were seen in UB and BB, but in AB a Cushing response could not be sustained. In UB, cerebral blood flow (CBF) decreased 50%, coronary blood flow (CoBF) increased 120%, and peripheral tissue blood flow was reduced only in the kidneys (18%) and the intestines (small 22%, large 35%). Blood flow to the other viscera, skin, and skeletal muscle was unchanged. CO (16%) and heart rate (HR, 38%) decreased, and total peripheral resistance (TPR, 68%) and stroke volume (SV, 38%) increased. In BB, CBF decreased 50%, CoBF decreased 20%, and blood flow was reduced 40-80% in all peripheral tissues. CO (69%) and HR (62%) decreased, TPR increased 366%, and SV was unchanged. We conclude that the Cushing response in UB animals combines an alpha-receptor-mediated vasoconstriction with a beta-receptor cardiac stimulation. The beta-mechanism is neither necessary nor sufficient for the hypertension. However, the combination of alpha- and beta-adrenergic mechanisms maintains cardiac output and peripheral tissue blood flow relatively constant while producing a systemic hypertension.

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