Regional distribution of cerebral blood flow during exercise in dogs

1980 ◽  
Vol 48 (2) ◽  
pp. 213-217 ◽  
Author(s):  
P. M. Gross ◽  
M. L. Marcus ◽  
D. D. Heistad
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Distribution ◽  
Moderate Intensity ◽  
Regional Cerebral Blood ◽  
Arterial Pco2 ◽  
Regional Flow ◽  
Arterial Blood ◽  
The Brain ◽  
Cerebral Vascular Resistance

This study was performed to determine whether exercise produces vasodilatation in regions of the brain that are associated with motor functions despite the associated vasoconstrictor effect of hypocapnia. Total and regional cerebral blood flow (CBF) were measured with microspheres in dogs during treadmill exercise of moderate intensity. Flow was also measured at rest after stimulation of ventilation with doxapram. During moderate exercise, total CBF was not changed significantly, but regional flow was increased in structures associated with motor-sensory control; blood flow to motor-sensory cortex, neocerebellar and paleocerebellar cortex, and spinal cord increased 30 +/- 7%, 39 +/- 8%, and 29 +/- 4%, respectively (P less than 0.05). After doxapram, which increased arterial blood pressure and decreased arterial PCO2 to levels similar to those during exercise, total CBF decreased and there was no redistribution of CBF. These results indicate that exercise in conscious dogs increases blood flow in regions of the brain associated with movement despite the associated vasoconstrictor stimulus of arterial hypocapnia. Thus, during exercise, local dilator influences that presumably result from increases in metabolism predominate over a potent constrictor stimulus in regulation of cerebral vascular resistance.

Chemical regulation of cerebral blood flow in turtles

1991 ◽  
Vol 260 (2) ◽  
pp. R382-R384 ◽  
Author(s):  
D. G. Davies
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Anaerobic Metabolism ◽  
Extracellular Fluid ◽  
Freshwater Turtles ◽  
Arterial Pco2 ◽  
Arterial Blood ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
Cerebral Vascular Resistance

This study was performed to test the effect of the chemical composition of the blood on cerebral blood flow (CBF) regulation in turtles. The CBF response to increases in arterial PCO2 (PaCO2) (hypercapnia) was measured during normoxia and anoxia in anesthetized freshwater turtles Pseudemys scripta. The radioactive-microsphere technique was used to measure CBF. CBF increased with increases in PaCO2. The sensitivity of the CBF response to hypercapnia (delta CBF/delta PaCO2) was 0.68 ml.min-1.100 g-1. Torr-1 during normoxia. delta CBF/delta PaCO2 increased to 3.44 ml.min-1.100 g-1. Torr-1 during anoxia. The increases in CBF occurred at constant mean arterial blood pressure, which indicates that cerebral vascular resistance decreased. The increased CBF response during asphyxia (hypercapnia-anoxia) could be beneficial for survival during prolonged dives by increasing glucose delivery for brain anaerobic metabolism. In addition, increased CBF could aid in regulating brain acid-base composition by controlling extracellular fluid PCO2.

Effects of striatal nitric oxide production on regional cerebral blood flow and seizure development in rats exposed to extreme hyperoxia

2015 ◽  
Vol 119 (11) ◽  
pp. 1282-1288 ◽  
Author(s):  
Heath G. Gasier ◽  
Ivan T. Demchenko ◽  
Barry W. Allen ◽  
Claude A. Piantadosi
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Brain Structures ◽  
Nitric Oxide Production ◽  
Regional Cerebral Blood ◽  
Oxide Production ◽  
Arterial Blood ◽  
The Brain

The endogenous vasodilator and signaling molecule nitric oxide has been implicated in cerebral hyperemia, sympathoexcitation, and seizures induced by hyperbaric oxygen (HBO2) at or above 3 atmospheres absolute (ATA). It is unknown whether these events in the onset of central nervous system oxygen toxicity originate within specific brain structures and whether blood flow is diverted to the brain from peripheral organs with high basal flow, such as the kidney. To explore these questions, total and regional cerebral blood flow (CBF) were measured in brain structures of the central autonomic network in anesthetized rats in HBO2at 6 ATA. Electroencephalogram (EEG) recordings, cardiovascular hemodynamics, and renal blood flow (RBF) were also monitored. As expected, mean arterial blood pressure and total and regional CBF increased preceding EEG spikes while RBF was unaltered. Of the brain structures examined, the earliest rise in CBF occurred in the striatum, suggesting increased neuronal activation. Continuous unilateral or bilateral striatal infusion of the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester attenuated CBF responses in that structure, but global EEG discharges persisted and did not differ from controls. Our novel findings indicate that: 1) cerebral hyperemia in extreme HBO2in rats does not occur at the expense of renal perfusion, highlighting the remarkable autoregulatory capability of the kidney, and 2) in spite of a sentinel increase in striatal blood flow, additional brain structure(s) likely govern the pathogenesis of HBO2-induced seizures because EEG discharge latency was unchanged by local blockade of striatal nitric oxide production and concomitant hyperemia.

Effect of Histamine on Regional Cerebral Blood Flow in Man

Cephalalgia ◽  
1982 ◽  
Vol 2 (1) ◽  
pp. 15-18 ◽  
Author(s):  
Annette Æbelholt Krabbe ◽  
Jes Olesen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Resting State ◽  
Regional Cerebral Blood Flow ◽  
Regional Distribution ◽  
Regional Cerebral Blood ◽  
Arterial Blood ◽  
Significant Change ◽  
Change In Mean

Regional cerebral blood flow (rCBF) was measured using the intra-arterial 133Xe technique in 35 or 256 areas of a hemisphere. In seven patients rCBF was measured in the resting state and following intracarotid (i.c.) infusion of histamine 10–50 μg/min. In four patients histamine was infused intravenously in a dose of 25–40 μg/min. Histamine caused no significant change in mean arterial blood pressure or arterial PCO2. There was no significant change in mean hemispheric blood flow during i.v. or i.c. histamine infusion. No change in the regional distribution of hemispheric blood flow was observed. Experimental histamine headache is most likely of extracranial origin.

Effect of acetazolamide on cerebral blood flow and capillary patency

1992 ◽  
Vol 73 (5) ◽  
pp. 1756-1761 ◽  
Author(s):  
H. M. Frankel ◽  
E. Garcia ◽  
F. Malik ◽  
J. K. Weiss ◽  
H. R. Weiss
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Gases ◽  
Capillary Perfusion ◽  
Arterial Pco2 ◽  
Arterial Blood ◽  
Cerebral Capillary ◽  
The Brain

This study investigated the effects 2 h after administration of acetazolamide on cerebral blood flow and the pattern of cerebral capillary perfusion. Arterial blood pressure, heart rate, arterial blood gases, and pH were recorded in two groups of rats along with either regional cerebral blood flow or the percentage of capillary volume per cubic millimeter and number per square millimeter perfused as determined in cortical, thalamic, pontine, and medullary regions of the brain. Blood pressure, heart rate, and arterial PCO2 were not significantly different between the rats receiving acetazolamide (100 mg/kg) and the controls. Arterial blood pH was significantly lower in the acetazolamide rats. Blood flow increased significantly in the cortical (+ 102%), thalamic (+ 89%), and pontine (+ 88%) regions receiving acetazolamide. In control rats, approximately 60% of the capillaries were perfused in all of the examined regions. The percentage of capillaries per square millimeter perfused was significantly greater in the cortical (+ 52%), thalamic (+ 49%), and pontine (+ 47%) regions of acetazolamide rats compared with controls. In the medulla the increases in blood flow and percentage of capillaries perfused were not significant. Thus in the regions that acetazolamide increased cerebral blood flow, it also increased the percentage of capillaries perfused.

Distribution of regional cerebral blood flow in voluntarily diving rats.

1998 ◽  
Vol 201 (4) ◽  
pp. 549-558
Author(s):  
G P Ollenberger ◽  
N H West
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regional Distribution ◽  
Detailed Examination ◽  
Brain Regions ◽  
Regional Cerebral Blood ◽  
Output Only ◽  
Almost All ◽  
The Brain

The distribution of regional cerebral blood flow (rCBF) was examined in conscious, voluntarily diving rats using the brain blood flow tracer N-[14C]isopropyl-p-iodoamphetamine and quantitative autoradiography. A detailed examination of the regional distribution of cerebral blood flow revealed that almost all brain regions were hyperperfused during diving. During diving, rCBF increased by an average of 1.7-fold in 29 of the 33 brain regions examined, despite a 69.2 % decrease in cardiac output. Only some regions of the basal ganglia (caudate-putamen and globus pallidus) and limbic areas (hippocampus and amygdala) did not increase rCBF significantly during diving. We determined that the increase in rCBF during diving is primarily due to a corresponding 20.9 % decrease in cerebrovascular resistance. A significant increase in perfusion pressure during diving also potentially contributed to the increase in rCBF. Because some brain regions did not increase flow significantly during diving, these results suggest that not all brain regions participate equally in the global cerebrovascular response to diving. This study provides evidence to support the view that the brain is preferentially perfused during conscious voluntary diving in the rat. The mechanism(s) that probably produce the cerebrovascular changes during diving are discussed.

Vorläufige Ergebnisse von 99mTc-HMPAO-SPECT-Untersuchungen bei endogenen Psychosen

1989 ◽  
Vol 28 (03) ◽  
pp. 88-91
Author(s):  
J. Schröder ◽  
H. Henningsen ◽  
H. Sauer ◽  
P. Georgi ◽  
K.-R. Wilhelm
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regions Of Interest ◽  
Post Mortem ◽  
Regional Cerebral Blood ◽  
Hmpao Spect ◽  
Endogenous Psychoses ◽  
The Brain ◽  
99Mtc Hmpao

18 psychopharmacologically treated patients (7 schizophrenics, 5 schizoaffectives, 6 depressives) were studied using 99mTc-HMPAO-SPECT of the brain. The regional cerebral blood flow was measured in three transversal sections (infra-/supraventricular, ventricular) within 6 regions of interest (ROI) respectively (one frontal, one parietal and one occipital in each hemisphere). Corresponding ROIs of the same section in each hemisphere were compared. In the schizophrenics there was a significantly reduced perfusion in the left frontal region of the infraventricular and ventricular section (p < 0.02) compared with the data of the depressives. The schizoaffectives took an intermediate place. Since the patients were treated with psychopharmaca, the result must be interpreted cautiously. However, our findings seem to be in accordance with post-mortem-, CT- and PET-studies presented in the literature. Our results suggest that 99mTc-HMPAO-SPECT may be helpful in finding cerebral abnormalities in endogenous psychoses.

scholarly journals Use of 19F NMR Spectroscopy for Measurement of Cerebral Blood Flow: A Comparative Study Using Microspheres

1989 ◽  
Vol 9 (6) ◽  
pp. 886-891 ◽  
Author(s):  
David Barranco ◽  
Leslie N. Sutton ◽  
Sandra Florin ◽  
Joel Greenberg ◽  
Teresa Sinnwell ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Blood ◽  
Radioactive Microsphere ◽  
Low Concentrations ◽  
Cat Brain ◽  
Nmr Techniques ◽  
High Concentrations ◽  
Washout Curves ◽  
The Brain

19F NMR was used to determine washout curves of an inert, diffusible gas (CHF3) from the cat brain. The cerebral blood flow was estimated from a bi- or tri-phasic fit to the deconvoluted wash-out curve, using the Kety-Schmidt approach. Cerebral blood flow values determined by 19F NMR show the expected responsiveness to alterations in Paco2, but are approximately 28% lower than cerebral blood flow values determined simultaneously by radioactive microsphere techniques. High concentrations of CHF3 have little effect on intracranial pressure, mean arterial blood pressure or Paco2, but cause small changes in the blood flow to certain regions of the brain. We conclude that 19F NMR techniques utilizing low concentrations of CHF3 have potential for the noninvasive measurement of cerebral blood flow.

Vasodilation of cat cerebral arterioles by prostaglandins D2, E2, G2, and I2

1979 ◽  
Vol 237 (3) ◽  
pp. H381-H385 ◽  
Author(s):  
E. F. Ellis ◽  
E. P. Wei ◽  
H. A. Kontos
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Blood Pressure ◽  
Standard Error ◽  
Arterial Blood ◽  
Cerebral Arterioles ◽  
The Mean ◽  
Dose Dependent ◽  
The Brain

To determine the possible role that endogenously produced prostaglandins may play in the regulation of cerebral blood flow, the responses of cerebral precapillary vessels to prostaglandins (PG) D2, E2, G2, and I2 (8.1 X 10(-8) to 2.7 X 10(-5) M) were studied in cats equipped with cranial windows for direct observation of the microvasculature. Local application of PGs induced a dose-dependent dilation of large (greater than or equal to 100 microns) and small (less than 100 microns) arterioles with no effect on arterial blood pressure. The relative vasodilator potency was PGG2 greater than PGE2 greater than PGI2 greater than PGD2. With all PGs, except D2, the percent dilation of small arterioles was greater than the dilation of large arterioles. After application of prostaglandins in a concentration of 2.7 X 10(-5) M, the mean +/- standard error of the percent dilation of large and small arterioles was, respectively, 47.6 +/- 2.7 and 65.3 +/- 6.1 for G2, 34.1 +/- 2.0, and 53.6 +/- 5.5 for E2, 25.4 +/- 1.8, and 40.2 +/- 4.6 for I2, and 20.3 +/- 2.5 and 11.0 +/- 2.2 for D2. Because brain arterioles are strongly responsive to prostaglandins and the brain can synthesize prostaglandins from its large endogenous pool of prostaglandin precursor, prostaglandins may be important mediators of changes in cerebral blood flow under normal and abnormal conditions.

Cerebral blood flow, glucose use, and CSF ionic regulation in potassium-depleted rats

1988 ◽  
Vol 254 (2) ◽  
pp. H250-H257
Author(s):  
H. Schrock ◽  
W. Kuschinsky
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Glucose Utilization ◽  
Local Cerebral Blood Flow ◽  
Arterial Pco2 ◽  
Average Decrease ◽  
K Concentration ◽  
Low K ◽  
The Brain ◽  
K Depletion

Rats were kept on a low-K+ diet for 25 or 70 days. Local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were measured in 31 different structures of the brain by means of the [14C]iodoantipyrine and [14C]2-deoxy-D-glucose method. After 25 and 70 days of K+ depletion LCBF was decreased significantly in 27 and 30 structures, respectively, the average decrease being 19 and 25%. In contrast, average LCGU was not changed. Cisternal cerebrospinal fluid (CSF) K+ concentration decreased significantly from 2.65 +/- 0.02 mM in controls to 2.55 +/- 0.02 mM and 2.47 +/- 0.02 mM in the two treated groups (P less than 0.01). CSF [HCO3-], pH, and PCO2 were increased in K+-depleted animals. These data show that K+ depletion induces an increase in CSF pH and a decrease in CSF K+ concentration, both of which cause a reduction in cerebral blood flow. The increased CSF PCO2 is secondary to the reduction of blood flow, since brain metabolism and arterial PCO2 remained constant.

scholarly journals Regional Cerebral Blood Flow in Patients with Aneurysms: Estimation by Xenon 133 Inhalation

1978 ◽  
Vol 5 (3) ◽  
pp. 301-305 ◽  
Author(s):  
Bryce Weir ◽  
Devidas Menon ◽  
Thomas Overton
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Normal Values ◽  
Regional Distribution ◽  
Progressive Increase ◽  
Control Group ◽  
Regional Cerebral Blood ◽  
Progressive Reduction ◽  
Distribution Of Flow

SUMMARY:Seventy six regional cerebral blood flow (rCBF) studies were conducted on 32 patients who had a total of 39 aneurysms. Twenty three of these patients were studied pre- and post-operatively. Normal values were obtained from a control group of 33 subjects, each of whom underwent one rCBF study. Flow was reduced following subarachnoid hemorrhage (SAH); it increased significantly postoperatively. Lower flows were associated with poorer clinical grades. There was a greater variation in regional distribution of flow immediately following SAH than in normals or in patients who had recovered from the acute phase. rCBF studies correlated with CT scans demonstrated that a progressive increase in ventricular size was accompanied by a progressive reduction in flow. In addition, intraventricular hemorrhage (IVH) was associated with a significant reduction in cerebral blood flow (CBF). No significant correlation between CBF and spasm was demonstrable.

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