Acute endoneurial ischemia induced by epineurial endothelin in the rat sciatic nerve

1992 ◽  
Vol 263 (6) ◽  
pp. H1806-H1810 ◽  
Author(s):  
D. W. Zochodne ◽  
L. T. Ho ◽  
P. M. Gross
Keyword(s):  
Blood Flow ◽  
Conduction Block ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Endoneurial Blood Flow ◽  
Reversible Ischemia ◽  
Potent Vasoconstrictor ◽  
Microvascular Resistance ◽  
Vasoconstrictor Peptide ◽  
Ca2 Channels

Endothelin (ET) is a potent vasoconstrictor peptide that may have pathophysiological roles in the microcirculation of the peripheral nervous system. We examined the local action of epineurial ET-1 on sciatic endoneurial blood flow using serial hydrogen clearance measurements in anesthetized, paralyzed, and ventilated Sprague-Dawley rats. In separate rats, we made serial measurements of sciatic motor multifiber conduction before and then after application of epineurial ET (saline on contralateral nerve) 2 and 24 h and 4 and 7 days later. Epineurial bathing solutions of ET increased microvascular resistance and reduced local endoneurial blood flow in a dose-responsive fashion with a half-maximum effective concentration of 10(-8) M. Maximum vasoconstriction at 10(-6) M ET was associated with a fall in endoneurial blood flow from 18.7 (pre-ET) to 7.2 ml x 100 g-1 x min-1. Epineurial norepinephrine (10(-7) to 10(-10) M) also resulted in vasoconstriction, but of lesser degree. Pretreatment with intraperitoneal nimodipine, a dihydropyridine Ca2+ channel antagonist, but not phentolamine, prevented the vasoconstrictive action of ET. Three of eight animals developed temporary but complete axonal conduction block at the site of ET administration (10(-5) M) and four others had partial conduction block. Contralateral saline-treated sciatic fibers were unaffected. Local ET action on extrinsic epineurial microvessels results in reversible ischemia of the underlying endoneurium that may be associated with conduction block. ET's action is more potent than norepinephrine and appears dependent on L-type voltage-gated Ca2+ channels.

Blood flow in normal and denervated muscle during exercise in conscious rats

1988 ◽  
Vol 255 (6) ◽  
pp. H1509-H1515 ◽  
Author(s):  
M. D. Delp ◽  
R. B. Armstrong
Keyword(s):  
Blood Flow ◽  
Muscular Activity ◽  
Sprague Dawley ◽  
Blood Flows ◽  
Sprague Dawley Rats ◽  
Mechanical Factors ◽  
Denervated Muscles ◽  
Gastrocnemius Muscles ◽  
Low Intensity Exercise ◽  
Hyperemic Response

The purpose of this study was to test the hypothesis that extrinsic mechanical factors, i.e., the dynamic shortening and lengthening imposed on a muscle during limb movements and the rhythmic compressions as surrounding muscles contract and relax, contribute to the initial muscle hyperemia during locomotion in conscious male Sprague-Dawley rats. Soleus and lateral head of gastrocnemius muscles were surgically denervated in one hindlimb several hours before exercise to remove 1) local metabolic vasodilator effects, 2) vasoconstrictor or vasodilatory influences mediated through sympathetic postganglionic fibers, and 3) intrinsic mechanical pumping. Blood flow was measured with radioactive microspheres during preexercise and at 30 s and 5 min of exercise in rats walking at 15 m/min or a motor-driven treadmill. Glycogen concentrations were also measured as an indicator of muscular activity to verify the denervation. Blood flows to control muscles in the normal limb were similar to previously reported values during preexercise and exercise. Denervation, however, decreased preexercise blood flow (69–88%) to muscle composed predominantly of oxidative fibers and increased flow (53%) to muscle composed predominantly of glycolytic fibers. During exercise, blood flow to denervated muscles either remained unchanged or decreased. These data suggest that extrinsic mechanical factors do not significantly contribute to the initial hyperemic response at the onset of low-intensity exercise in normal muscle.

scholarly journals Duct ligation and pancreatic islet blood flow in rats: physiological growth of islets does not affect islet blood perfusion

2005 ◽  
Vol 153 (2) ◽  
pp. 345-351 ◽  
Author(s):  
Leif Jansson ◽  
Birgitta Bodin ◽  
Örjan Källskog ◽  
Arne Andersson
Keyword(s):  
Blood Flow ◽  
Pancreatic Islet ◽  
Serum Insulin ◽  
Blood Perfusion ◽  
Islet Function ◽  
Sprague Dawley ◽  
Islet Mass ◽  
Islet Blood Flow ◽  
Sprague Dawley Rats ◽  
Duct Ligation

Objectives: The aim of this study was to evaluate islet blood-flow changes during stimulated growth of the islet organ without any associated functional impairment of islet function. Design: A duct ligation encompassing the distal two-thirds of the pancreas was performed in adult, male Sprague–Dawley rats. Methods: Pancreatic islet blood flow was measured in duct-ligated and sham-operated rats 1, 2 or 4 weeks after surgery. In some animals studied 4 weeks after surgery, islet blood flow was also measured also during hyperglycaemic conditions. Results: A marked atrophy of the exocrine pancreas was seen in all duct-ligated rats. Blood glucose and serum insulin concentrations were normal. An increased islet mass was only seen 4 weeks after surgery. No differences in islet blood perfusion were noted at any time point after duct ligation. In both sham-operated and duct-ligated rats islet blood flow was increased during hyperglycaemia; the response was, however, slightly more pronounced in the duct-ligated part of the gland. Conclusions: Normal, physiological islet growth does not cause any major changes in the islet blood perfusion or its regulation. This is in contrast to findings during increased functional demands on the islets or during deteriorated islet function, when increased islet blood flow is consistently seen.

scholarly journals Mumefural Improves Blood Flow in a Rat Model of FeCl3-Induced Arterial Thrombosis

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3795
Author(s):  
Jihye Bang ◽  
Won Kyung Jeon
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Rat Model ◽  
Arterial Thrombosis ◽  
Thrombus Formation ◽  
Sprague Dawley ◽  
Fiber Damage ◽  
Sprague Dawley Rats ◽  
Related Proteins

Mumefural (MF), a bioactive component of the processed fruit of Prunus mume Sieb. et Zucc, is known to inhibit platelet aggregation induced by agonists in vitro. In this study, we investigated the anti-thrombotic effects of MF using a rat model of FeCl3-induced arterial thrombosis. Sprague–Dawley rats were intraperitoneally injected with MF (0.1, 1, or 10 mg/kg) 30 min before 35% FeCl3 treatment to measure the time to occlusion using a laser Doppler flowmeter and to assess the weight of the blood vessels containing thrombus. MF treatment significantly improved blood flow by inhibiting occlusion and thrombus formation. MF also prevented collagen fiber damage in injured vessels and inhibited the expression of the platelet activation-related proteins P-selectin and E-selectin. Moreover, MF significantly reduced the increased inflammatory signal of nuclear factor (NF)-κB, toll-like receptor 4 (TLR4), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in blood vessels. After administration, MF was detected in the plasma samples of rats with a bioavailability of 36.95%. Therefore, we suggest that MF may improve blood flow as a candidate component in dietary supplements for improving blood flow and preventing blood circulation disorders.

Role of leukocytes in uterine hypoperfusion and fetal growth retardation induced by ischemia-reperfusion

2001 ◽  
Vol 280 (3) ◽  
pp. H1215-H1221 ◽  
Author(s):  
Kei Miyakoshi ◽  
Hitoshi Ishimoto ◽  
Osamu Nishimura ◽  
Shinji Tanigaki ◽  
Mamoru Tanaka ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fetal Growth ◽  
Growth Retardation ◽  
Ischemia Reperfusion ◽  
Fetal Growth Retardation ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
Doppler Flowmetry ◽  
Leukocyte Accumulation ◽  
Sprague Dawley Rats

We investigated leukocyte involvement in uterine hypoperfusion and intrauterine fetal growth retardation (IUGR) induced by ischemia-reperfusion (I/R) in Sprague-Dawley rats. On day 17 of gestation, leukocyte accumulation in the uterus and placenta subjected to 30 min of ischemia, followed by reperfusion, was assessed by measuring myeloperoxidase (MPO) activity. Uterine MPO activity was significantly higher after 1 h of reperfusion than it was before ischemia ( P < 0.05), without any increase in placental MPO activity. Immunohistochemical staining showed leukocyte accumulation in the uterus subjected to I/R. The effects of treatment with monoclonal antibodies against CD11a (WT1) and CD18 (WT3) at a dose of 0.8 mg/kg on uterine blood flow and IUGR were investigated. Laser-Doppler flowmetry demonstrated that uterine hypoperfusion at 2 h after ischemia (blood flow, −51.7 ± 1.2%; P < 0.01) was inhibited by WT1 and WT3 treatment. I/R-induced IUGR at full term ( P < 0.05 vs. nonischemic horn) was prevented by WT1 and WT3 treatment on day 17. These results indicate that leukocyte accumulation may play an important role in the pathogenesis of uterine hypoperfusion and IUGR induced by I/R in pregnant rats.

Salutary effects of androstenediol on cardiac function and splanchnic perfusion after trauma-hemorrhage

2004 ◽  
Vol 287 (2) ◽  
pp. R386-R390 ◽  
Author(s):  
Tomoharu Shimizu ◽  
Mashkoor A. Choudhry ◽  
Laszlo Szalay ◽  
Loring W. Rue ◽  
Kirby I. Bland ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Function ◽  
Cytokine Production ◽  
Cardiovascular Function ◽  
Organ Blood Flow ◽  
Sprague Dawley ◽  
Splanchnic Perfusion ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
Circulating Levels

Recent studies have shown that dehydroepiandrosterone (DHEA) administration after trauma-hemorrhage (T-H) improves cardiovascular function and decreases cytokine production in male animals. Although androstenediol, one of the metabolites of DHEA, is reported to have estrogen-like activity, it remains unknown whether androstenediol per se has any salutary effects on cytokines and cardiovascular function after T-H. To examine this effect, male Sprague-Dawley rats underwent laparotomy and were bled to and maintained at a mean arterial blood pressure of 35–40 mmHg for ∼90 min. The animals were resuscitated with four times the volume of maximal bleedout volume in the form of Ringer lactate. Androstenediol (1 mg/kg body wt iv) or vehicle was administered at the end of resuscitation. Twenty-four hours after resuscitation, cardiac function and organ blood flow were measured by using 85Sr-microspheres. Circulating levels of nitrate/nitrite and IL-6 were also determined. Cardiovascular function and organ blood flow were significantly depressed after T-H. However, these parameters were restored by androstenediol treatment. The elevated plasma IL-6 levels after T-H were also lowered by androstenediol treatment. In contrast, plasma levels of nitrate/nitrite were the highest in the androstenediol-treated T-H animals. Because androstenediol administration after T-H decreases cytokine production and improves cardiovascular function, this agent appears to be a novel and useful adjunct for restoring the depressed cardiovascular function and for cytokine production in males after adverse circulatory conditions.

scholarly journals Cocaine- and Amphetamine-Regulated Transcript (CART) Peptide: A Vasoactive Role in the Cerebral Circulation

2005 ◽  
Vol 25 (10) ◽  
pp. 1376-1385 ◽  
Author(s):  
Jeffrey J Iliff ◽  
Nabil J Alkayed ◽  
Kiarash J Gloshani ◽  
Richard J Traystman ◽  
G Alexander West
Keyword(s):  
Cerebral Circulation ◽  
Vascular Response ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Injury Model ◽  
Cart Peptide ◽  
Cerebral Arterioles ◽  
Specific Antagonist ◽  
Potent Vasoconstrictor ◽  
Dose Dependent

Cocaine- and amphetamine-regulated transcript (CART) peptides are known to be involved in the stress response and have been implicated in the regulation of the cardiovascular system. We evaluated the direct vasoactive properties of CART in the cerebral circulation and its potential mechanisms of action. Penetrating cerebral arterioles, isolated from male Sprague—Dawley rats, were cannulated using a concentric micropipette setup, pressurized and perfused. The vascular response to intraluminal and extraluminal CART peptide was characterized. The endothelium dependence of this response was assessed by means of the endothelial light—dye injury model. The nonspecific endothelin receptor antagonist PD-145065, the ETA-specific antagonist BQ-123, the ETB-specific antagonist BQ-788, and the inhibitor of endothelin-converting enzyme phosphoramidon were used to characterize the involvement of the endothelin pathway in the vascular response to CART peptide. Extraluminal and intraluminal application of CART peptide (0.1 nm to 1 μmol/L) evoked a long-lasting dose-dependent constriction of isolated penetrating cerebral arterioles to ~80% of resting myogenic tone. Disruption of the endothelium by the endothelial light/dye injury model resulted in the abolition of this response ( P<0.05). Extraluminal administration of PD-145065, BQ-123, and phosphoramidon blocked the constriction response to CART peptide ( P<0.01). The ETB antagonist, BQ-788, did not alter the constriction response to CART peptide. Cocaine- and amphetamine-regulated transcript peptide is a potent vasoconstrictor in the cerebral circulation. Its direct vasoactive properties are endothelium-dependent and are mediated by ETA, not ETB, endothelin receptors.

Concurrent increases in regional hematocrit and blood flow in diabetic rats: prevention by sorbinil

1992 ◽  
Vol 263 (3) ◽  
pp. H945-H950 ◽  
Author(s):  
S. P. Sutera ◽  
K. Chang ◽  
J. Marvel ◽  
J. R. Williamson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Sciatic Nerve ◽  
Diabetic Rats ◽  
Sprague Dawley ◽  
Citrate Buffer ◽  
Ocular Tissues ◽  
Arterial Blood ◽  
Transit Times ◽  
Sprague Dawley Rats

These studies were undertaken to investigate the relationship between regional hemodynamic and hemorheological changes in the microvasculature of diabetic rats. Diabetes was induced in male Sprague-Dawley rats by injection of streptozotocin (55 mg/kg body wt). Control rats were injected with vehicle (sodium citrate buffer). A subgroup of diabetic rats was treated with an aldose reductase inhibitor (sorbinil) added to the diet in an amount to provide a daily dose of approximately 0.2 mmol.kg-1.day-1. Three weeks later all animals were anesthetized with thiobutabarbital sodium (Inactin, 100 mg/kg injected intraperitoneally) for assessment of blood flow (by injection of 15 microns microspheres) and regional hematocrit (determined by isotope-dilution techniques using 51Cr-labeled red blood cells and 125I-labeled bovine serum albumin) in selected tissues. The hematocrit in arterial blood samples was identical (approximately 46%) in controls and in diabetics. Regional hematocrits were much lower than arterial hematocrits in control rats and ranged from approximately 20% in ocular tissues, sciatic nerve, diaphragm, and skin to approximately 30% in brain, skeletal muscle, heart, and fat. Hematocrits of diabetic rats were markedly increased in ocular tissues, sciatic nerve, and skin but not in brain, heart, or skeletal muscle. These increases in regional hematocrit were associated with increases in blood flow and were largely prevented by sorbinil. Diabetes induced significant decreases in the mean transit times for whole blood and erythrocytes in all tissues examined except brain, retina, and skin.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Hindlimb unweighting decreases endothelium-dependent dilation and eNOS expression in soleus not gastrocnemius

2001 ◽  
Vol 91 (3) ◽  
pp. 1091-1098 ◽  
Author(s):  
Christopher R. Woodman ◽  
William G. Schrage ◽  
James W. E. Rush ◽  
Chester A. Ray ◽  
Elmer M. Price ◽  
...  
Keyword(s):  
Blood Flow ◽  
Protein Content ◽  
Sprague Dawley ◽  
Enos Expression ◽  
Hindlimb Unweighting ◽  
Sprague Dawley Rats ◽  
Mrna Content ◽  
Enos Mrna ◽  
Endothelial Nitric Oxide

We tested the hypothesis that hindlimb unweighting (HLU) decreases endothelium-dependent vasodilation and expression of endothelial nitric oxide synthase (eNOS) and superoxide dismutase-1 (SOD-1) in arteries of skeletal muscle with reduced blood flow during HLU. Sprague-Dawley rats (300–350 g) were exposed to HLU ( n = 15) or control ( n = 15) conditions for 14 days. ACh-induced dilation was assessed in muscle with reduced [soleus (Sol)] or unchanged [gastrocnemius (Gast)] blood flow during HLU. eNOS and SOD-1 expression were measured in feed arteries (FA) and in first-order (1A), second-order (2A), and third-order (3A) arterioles. Dilation to infusion of ACh in vivo was blunted in Sol but not Gast. In arteries of Sol muscle, HLU decreased eNOS mRNA and protein content. eNOS mRNA content was significantly less in Sol FA (35%), 1A arterioles (25%) and 2A arterioles (18%). eNOS protein content was less in Sol FA (64%) and 1A arterioles (65%) from HLU rats. In arteries of Gast, HLU did not decrease eNOS mRNA or protein. SOD-1 mRNA expression was less in Sol 2A arterioles (31%) and 3A arterioles (29%) of HLU rats. SOD-1 protein content was less in Sol FA (67%) but not arterioles. SOD-1 mRNA and protein content were not decreased in arteries from Gast. These data indicate that HLU decreases endothelium-dependent vasodilation, eNOS expression, and SOD-1 expression primarily in arteries of Sol muscle where blood flow is reduced during HLU.

Effect of naloxone on regional cerebral blood flow during endotoxin shock in conscious rats

1987 ◽  
Vol 253 (3) ◽  
pp. R425-R433
Author(s):  
W. R. Law ◽  
J. L. Ferguson
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Endotoxin Shock ◽  
Sprague Dawley ◽  
Regional Cerebral Blood ◽  
Large Share ◽  
Flow Measurements ◽  
Sprague Dawley Rats ◽  
The Right

Maintenance of cerebral blood flow (CBF) is vital during cardiovascular shock. Since opioids have been implicated in the pathophysiology of endotoxin shock and have been shown to alter cerebral perfusion patterns, we determined whether opioids were responsible for any of the changes in regional CBF observed during endotoxin shock and whether the use of naloxone might impair or aid in the maintenance of CBF. When blood flow (BF) is studied with microspheres in rats, the left ventricle of the heart is often cannulated via the right carotid artery. Questions have arisen concerning the potential adverse effects of this method on CBF in the hemisphere ipsilateral to the ligated artery. We measured right and left regional CBF by use of this route of cannulation. Twenty-four hours after cannulations were performed, flow measurements were made using radiolabeled microspheres in conscious unrestrained male Sprague-Dawley rats (300-400 g) before and 10, 30 and 60 min after challenging with 10 mg/kg Escherichia coli endotoxin (etx) or saline. Naloxone (2 mg/kg) or saline was given as a treatment 25 min post-etx. We found no significant differences between right and left cortical, midbrain, or cerebellar BF at any time in any treatment group. After etx, the whole brain received a large share of the depressed cardiac output. Thus global CBF was not significantly reduced below its pre-etx value, an effect unaltered by naloxone. Regionally, BF was reduced to cerebellum and midbrain by 30 min post-etx. Naloxone prevented this depression. No region was affected to a greater or lesser degree than others.(ABSTRACT TRUNCATED AT 250 WORDS)

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