scholarly journals The role of adenosine in mediating vasodilatation in mesenteric circulation of the rat in acute and chronic hypoxia.

1995 ◽  
Vol 489 (1) ◽  
pp. 225-234 ◽  
Author(s):  
R Mian ◽  
J M Marshall
Keyword(s):  
Chronic Hypoxia ◽  
Mesenteric Circulation

Breathing and its stimulatory responses in parkinsonism: repercussions for physiotherapy

2020 ◽  
Author(s):  
Mieczyslaw Pokorski
Keyword(s):  
Experimental Study ◽  
Chronic Hypoxia ◽  
Motor Impairments

This study addresses respiratory and motor impairments in an experimental reserpine-induced model of parkinsonism in rats. The role of chronic hypoxia due to diminished ventilation in the development and course of neurodegeneration is addressed. An attempt was made to distinguish between central and peripheral dopamine pathways in the mechanisms of neurodegeneration. A dissociation of putative mechanisms of respiratory and motor impairments is tackled as well. Although this purely experimental study cannot be directly extrapolated to human pathophysiology, the corollaries have been drawn concerning the potential repercussions of the respiratory and motor impairments for the physiotherapeutic procedures in the management of chronic neurodegeneration.

Role of Rho kinases in PKG-mediated relaxation of pulmonary arteries of fetal lambs exposed to chronic high altitude hypoxia

2007 ◽  
Vol 292 (3) ◽  
pp. L678-L684 ◽  
Author(s):  
Yuansheng Gao ◽  
Ada D. Portugal ◽  
Sewite Negash ◽  
Weilin Zhou ◽  
Lawrence D. Longo ◽  
...  
Keyword(s):  
High Altitude ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Regulatory Subunit ◽  
Fourth Generation ◽  
Minor Effect ◽  
Altitude Hypoxia ◽  
High Altitude Hypoxia ◽  
Rock Activity

An increase in Rho kinase (ROCK) activity is implicated in chronic hypoxia-induced pulmonary hypertension. In the present study, we determined the role of ROCKs in cGMP-dependent protein kinase (PKG)-mediated pulmonary vasodilation of fetal lambs exposed to chronic hypoxia. Fourth generation pulmonary arteries were isolated from near-term fetuses (∼140 days of gestation) delivered from ewes exposed to chronic high altitude hypoxia for ∼110 days and from control ewes. In vessels constricted to endothelin-1, 8-bromoguanosine-cGMP (8-Br-cGMP) caused a smaller relaxation in chronically hypoxic (CH) vessels compared with controls. Rp-8-Br-PET-cGMPS, a PKG inhibitor, attenuated relaxation to 8-Br-cGMP in control vessels to a greater extent than in CH vessels. Y-27632, a ROCK inhibitor, significantly potentiated 8-Br-cGMP-induced relaxation of CH vessels and had only a minor effect in control vessels. The expression of PKG was increased but was not accompanied with an increase in the activity of the enzyme in CH vessels. The expression of type II ROCK and activity of ROCKs were increased in CH vessels. The phosphorylation of threonine (Thr)696 and Thr850 of the regulatory subunit MYPT1 of myosin light chain phosphatase was inhibited by 8-Br-cGMP to a lesser extent in CH vessels than in controls. The difference was eliminated by Y-27632. These results suggest that chronic hypoxia in utero attenuates PKG-mediated relaxation in pulmonary arteries, partly due to inhibition of PKG activity and partly due to enhanced ROCK activity. Increased ROCK activity may inhibit PKG action through increased phosphorylation of MYPT1 at Thr696 and Thr850.

ABNORMAL CAPILLARY MORPHOLOGY IN CONGENITAL HEART DISEASE

PEDIATRICS ◽  
1966 ◽  
Vol 37 (2) ◽  
pp. 316-322
Author(s):  
Stella B. Kontras ◽  
JoAnn G. Bodenbender
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Congenital Heart ◽  
Septal Defect ◽  
Chronic Hypoxia ◽  
Normal Children ◽  
Vascular Abnormalities ◽  
Definitive Surgery ◽  
Vascular Compartment

Capillary morphology has been studied in 111 normal children. In 98% of these cases, straight hairpin forms make up over 80% of the capillaries examined. Thirty children with congenital heart disease showed 80% abnormal capillary patterns consisting of dilated, tortuous, and branched loops. These were most marked in cyanotic tetralogy of Fallot and ventricular septal defect with pulmonary hypertension. These cases also were associated with microscopic hemorrhages, increased capillary fragility and actual postoperative hemorrhagic complications. Definitive surgery in two cases, though improving the patient, did not result in changes in the abnormal capillary patterns. It is suggested that the role of the capillary structure in rheology of blood in the microvasculature has largely been ignored and that abnormalities in this vascular compartment may affect perfusion of tissues. The association of abnormalities in coagulation studies, hemorrhage, and thrombosis with congenital heart disease may in part be related to the morphologic vascular abnormalities. The abnormal capillary findings may be due to maturational arrest or dysmaturity of this portion of the cardiovascular system or may be the result of chronic hypoxia.

scholarly journals Neuroprotective effect of secretin in chronic hypoxia induced neurodegeneration in rats

2017 ◽  
Vol 6 (2) ◽  
pp. 298
Author(s):  
Gowtham Padmanaban ◽  
M. K. Kayalvizhi ◽  
Kalyanasundaram Kasiviswanathan ◽  
Ruckmani Arunachalam ◽  
Vishnu Kumar Urkavalan
Keyword(s):  
Blood Flow ◽  
Amino Acid ◽  
Experimental Design ◽  
Rat Model ◽  
Chronic Hypoxia ◽  
Neuroprotective Effect ◽  
Proper Functioning ◽  
Partial Pressures

Background: Hypoxia is a condition in any stage in the delivery of oxygen to cells which include decreased partial pressures of oxygen, less diffusion of oxygen in the lungs, insufficient hemoglobin, inefficient blood flow to the end tissue, and breathing rhythm. Secretin is an amino acid which plays proper functioning of gastro intestinal system.Methods: The current study was conducted to evaluvate the effect of exogenously administrated secretin on chronic hypoxic damage of brain in rat model. Experimental design consists of control animals, Control animals + secretin hypoxia exposed animals; hypoxia exposed animals +secretin (20ng/kg.bw).Results: The results of this study point to a possible role of Secretin as neuroprotectant.Conclusions: Further research on secretin needs to be conducted in order to confirm the deductions made by this study.

scholarly journals Role of chronic hypoxia and hypoxia inducible factor in kidney disease

2008 ◽  
Vol 121 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Nangaku Masaomi ◽  
Nishi Hiroshi ◽  
Miyata Toshio
Keyword(s):  
Kidney Disease ◽  
Chronic Hypoxia ◽  
Hypoxia Inducible Factor
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