scholarly journals Effects of changes of blood pressure, respiratory acidosis and hypoxia on blood flow in the sciatic nerve of the rat.

1984 ◽  
Vol 347 (1) ◽  
pp. 513-524 ◽  
Author(s):  
P A Low ◽  
R R Tuck
2008 ◽  
Vol 26 (3) ◽  
pp. 145-148 ◽  
Author(s):  
Motohiro Inoue ◽  
Tatsuya Hojo ◽  
Miwa Nakajima ◽  
Hiroshi Kitakoji ◽  
Megumi Itoi ◽  
...  

Objective To investigate the mechanism of the clinical effect of electroacupuncture of the pudendal nerve on the lumbar and lower limb symptoms caused by lumbar spinal canal stenosis, we studied changes in sciatic nerve blood flow during electrical stimulation of the pudendal nerve in the rat. Methods Using rats (n=5), efferent electrical stimulation to the pudendal nerve was performed and sciatic nerve blood flow was measured with laser Doppler flowmetry. Simultaneously, changes in the blood pressure and cardiac rate were measured. Furthermore, the effect of atropine on these responses to the stimulation was also studied. Results Electrical stimulation of the pudendal nerve significantly increased blood flow in the sciatic nerve transiently without increasing heart rate and systemic blood pressure. The significant increase in the sciatic nerve blood flow disappeared after administration of atropine. Conclusion Electrical stimulation of the pudendal nerve causes a transient and significant increase in sciatic nerve blood flow. This response is eliminated or attenuated by administration of atropine, indicating that it occurs mainly via cholinergic nerves.


2005 ◽  
Vol 23 (4) ◽  
pp. 166-170 ◽  
Author(s):  
Motohiro Inoue ◽  
Tatsuya Hojo ◽  
Tadashi Yano ◽  
Yasukazu Katsumi

Introduction Acupuncture may have a role in the treatment of intermittent claudication of the cauda equina due to lumbar spinal canal stenosis. The aim of this study was to explore the possible physiological mechanisms. Methods In a laboratory experiment, manual acupuncture was performed at a point adjacent to the sixth lumbar vertebra of 13 animals and its effect on sciatic nerve blood flow was measured using a laser Doppler flowmetry. Simultaneously, changes in blood pressure and cardiac rate were observed. Each animal was stimulated four to eight times, making a total of 58 experiments. Results Acupuncture stimulation did not produce consistent changes in sciatic nerve blood flow, with increased and decreased blood flow as well as no change in blood flow observed. Among the 58 individual experiments, sciatic nerve blood flow was increased in 33, reduced in 12, and unchanged in 13. Approximately half of the stimulations showed a correlation between blood flow and blood pressure change. Conclusion Our results indicate that lumbar acupuncture stimulation can have an influence on sciatic nerve blood flow. The effect is dependent not only on blood pressure but also other factors, for example vasodilator and vasoconstrictor nerve activity. This mechanism may contribute to a clinical effect on intermittent claudication of the cauda equina.


2014 ◽  
Vol 11 (4) ◽  
pp. 281-289 ◽  
Author(s):  
T Dylan Olver ◽  
Kenneth N Grisé ◽  
Matthew W McDonald ◽  
Adwitia Dey ◽  
Matti D Allen ◽  
...  

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.


2008 ◽  
Vol 22 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Natalie Werner ◽  
Neval Kapan ◽  
Gustavo A. Reyes del Paso

The present study explored modulations in cerebral blood flow and systemic hemodynamics during the execution of a mental calculation task in 41 healthy subjects. Time course and lateralization of blood flow velocities in the medial cerebral arteries of both hemispheres were assessed using functional transcranial Doppler sonography. Indices of systemic hemodynamics were obtained using continuous blood pressure recordings. Doppler sonography revealed a biphasic left dominant rise in cerebral blood flow velocities during task execution. Systemic blood pressure increased, whereas heart period, heart period variability, and baroreflex sensitivity declined. Blood pressure and heart period proved predictive of the magnitude of the cerebral blood flow response, particularly of its initial component. Various physiological mechanisms may be assumed to be involved in cardiovascular adjustment to cognitive demands. While specific contributions of the sympathetic and parasympathetic systems may account for the observed pattern of systemic hemodynamics, flow metabolism coupling, fast neurogenic vasodilation, and cerebral autoregulation may be involved in mediating cerebral blood flow modulations. Furthermore, during conditions of high cardiovascular reactivity, systemic hemodynamic changes exert a marked influence on cerebral blood perfusion.


2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.


2019 ◽  
Vol 47 (7) ◽  
pp. 1007-1009
Author(s):  
Douglas S. DeWitt ◽  
Donald S. Prough

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