scholarly journals The Velocities of Red Cell and Plasma Flows through Parenchymal Microvessels of Rat Brain are Decreased by Pentobarbital

1993 ◽  
Vol 13 (3) ◽  
pp. 487-497 ◽  
Author(s):  
Ling Wei ◽  
Tadahiro Otsuka ◽  
Virgil Acuff ◽  
Daniel Bereczki ◽  
Karen Pettigrew ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Rat Brain ◽  
High Dose ◽  
Local Cerebral Blood Flow ◽  
Brain Areas ◽  
Transit Times ◽  
Flow Through ◽  
Distribution Spaces ◽  
Local Metabolism

Local cerebral blood flow is lowered in many brain areas of the rat by high-dose pentobarbital (50 mg/kg). In the present study, the mechanism of this flow change was examined by measuring the distribution of radiolabeled red blood cells (RBCs) and albumin (RISA) in small parenchymal microvessels and calculating the microvascular distribution spaces and mean transit times of RBCs, RISA, and blood. In most brain areas, pentobarbital slightly decreased the RISA space, modestly increased the RBC space, and did not alter the blood space. The mean transit times of RBCs, RISA, and blood through the perfused microvessels were considerably greater in treated rats than in controls. These findings indicate that the mechanism by which high-dose pentobarbital diminishes local cerebral blood flow in rat brain is, in the main, a lowered linear velocity of plasma and RBC flow through small parenchymal microvessels and not decreased percentage of perfused capillaries (capillary retirement). This response is probably driven mainly by lowered local metabolism and may well entail a slight increase in the number of small microvessels that are perfused by RBCs.

Hypercapnia slightly raises blood volume and sizably elevates flow velocity in brain microvessels

1993 ◽  
Vol 264 (5) ◽  
pp. H1360-H1369 ◽  
Author(s):  
D. Bereczki ◽  
L. Wei ◽  
T. Otsuka ◽  
F. J. Hans ◽  
V. Acuff ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Local Cerebral Blood Flow ◽  
Brain Areas ◽  
Brain Microvessels ◽  
Transit Times ◽  
Flow Through ◽  
The Mean ◽  
Distribution Spaces ◽  
Awake Rats

The increase in local cerebral blood flow (LCBF) caused by hypercapnia may be mainly accomplished by raising the velocity of plasma and/or red blood cell (RBC) flow through the microvessels and not by perfusing more capillaries. This suggestion was tested in awake rats exposed to 8% CO2 and in control rats. LCBF was measured by the 14C-labeled iodoantipyrine method. The volume of blood in small parenchymal microvessels was estimated from the distribution spaces of 125I-labeled serum albumin (RISA) and 55Fe-labeled RBCs. Hypercapnia elevated LCBF 2.0- to 3.5-fold in the 40 brain areas studied, marginally raised the RBC spaces, and significantly increased the RISA and whole blood distribution spaces (approximately 25 and 19%, respectively). These changes in microvessel distribution volumes could be the result of perfusing a slightly larger fraction of capillaries (recruitment), increasing microvessel diameter somewhat, or both. With hypercapnia, the mean transit times fell to approximately 45% of control, which indicated that LCBF was mainly increased by raising the velocity of RBC and plasma flow through already perfused microvessels. Overall, few, if any, capillaries or other microvessels were recruited by hypercapnia.

Variation in local cerebral blood flow response to high-dose pentobarbital sodium in the rat

1991 ◽  
Vol 261 (1) ◽  
pp. H110-H120 ◽  
Author(s):  
T. Otsuka ◽  
L. Wei ◽  
V. R. Acuff ◽  
A. Shimizu ◽  
K. D. Pettigrew ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Gray Matter ◽  
Intraperitoneal Administration ◽  
Brain Structures ◽  
High Dose ◽  
Local Cerebral Blood Flow ◽  
Brain Areas ◽  
Pentobarbital Sodium ◽  
High Doses

Microvascular bed structure and functions are known to vary throughout the brain. Microvascular responses to high doses of pentobarbital sodium might therefore differ among brain areas. This possibility was examined by measuring local cerebral blood flow (LCBF) with [14C]iodoantipyrine in 52 brain areas at 5, 10, 25, and 60 min after intraperitoneal administration of pentobarbital (50 mg/kg). From 5 to 60 min, LCBF was significantly lowered in 17 of 25 forebrain gray matter areas but in only 1 of 18 hindbrain gray matter structures, the pontine nuclei. Smaller, shorter duration lowering of LCBF was also observed in ten other brain areas. In both control and treated rats, LCBF was found to vary within individual brain structures. The pattern of these LCBF variations was columnar in the cerebral cortex and the hippocampus but was patchy in the caudate-putamen, thalamus, and inferior colliculus. These results indicate that pentobarbital anesthesia more strongly alters LCBF in the forebrain than in the hindbrain and produces different patterns of changes in LCBF than in local cerebral glucose utilization, which was measured with 2-deoxyglucose in a companion study.

Nicotine increases microvascular blood flow and flow velocity in three groups of brain areas

1993 ◽  
Vol 265 (6) ◽  
pp. H2142-H2150
Author(s):  
F. J. Hans ◽  
L. Wei ◽  
D. Bereczki ◽  
V. Acuff ◽  
J. Demaro ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mean Transit Time ◽  
Microvascular Blood Flow ◽  
Brain Areas ◽  
Nicotine Treatment ◽  
Nicotine Administration ◽  
Transit Times ◽  
Flow Through ◽  
Distribution Spaces ◽  
The Brain

To examine the mechanism of local cerebral blood flow (LCBF) elevation, nicotine (1.75 mg/kg sc) was administered to rats, and LCBF plus the distribution spaces of radiolabeled albumin (RISA) and red blood cells (RBC) in parenchymal microvessels were measured throughout the brain. Microvascular blood spaces and transit times were calculated from the data. From 1.5 to 3 min after nicotine administration, LCBF was raised by 40–150% in 16 of the brain areas and unaltered in the remaining 28 areas. The affected structures included parts of the visual-auditory, sensorimotor-cortical, and interpeduncular systems. RBC spaces were not changed by nicotine treatment. RISA and blood spaces were increased slightly but not significantly in some of the LCBF-affected areas but nowhere else. Nicotine seemingly elevates LCBF in the affected areas mainly by increasing linear velocity of flow through the microvascular beds. In agreement with this, mean transit time, which is inversely related to velocity, was decreased from 0.3-0.5 to approximately 0.2 s in the microvascular systems of the nicotine-affected areas.

scholarly journals Isn't functional neuroimaging all about Ca2+ signaling in astrocytes?

2015 ◽  
Vol 114 (3) ◽  
pp. 1353-1356 ◽  
Author(s):  
Mauro DiNuzzo
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Neuroimaging ◽  
Local Cerebral Blood Flow ◽  
The Past ◽  
Cereb Blood Flow ◽  
Intracellular Ca ◽  
Flow Through ◽  
Experimental Findings ◽  
Paradigm Shifting

Extensive research over the past decades about the multifaceted roles of brain astrocytes led to the suggestion that the signals observed with functional neuroimaging might primarily reflect astrocytic rather than neuronal activity. The basis for this paradigm-shifting concept was the evidence for an involvement of astrocytes in the control of local cerebral blood flow through intracellular Ca2+ signaling. In this Neuro Forum, I discuss new important experimental findings obtained by Jego et al. (Jego P, Pacheco-Torres J, Araque A, Canals S. J Cereb Blood Flow Metab 34: 1599–1603, 2014) as well as other closely related studies published recently, prompting a dismissal of substantial astrocytic contribution in functional neuroimaging.

Local cerebral blood flow in the rat brain during hypercapnia and hypoxia

1983 ◽  
Vol 118 (4) ◽  
pp. 439-440 ◽  
Author(s):  
MAJ-LIS SMITH ◽  
ERIK KÅGSTRÖM ◽  
BO K. SIESJÖ
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Rat Brain ◽  
Local Cerebral Blood Flow

Effect of transient reduction of cerebral blood flow on membrane anisotropy and lipid peroxidation in different rat brain areas

1994 ◽  
Vol 25 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Mira Melzacka ◽  
Nina Weiner ◽  
Christine Heim ◽  
Rainald Schmidt-Kastner ◽  
Maria Sieklucka ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Rat Brain ◽  
Brain Areas

scholarly journals Influence of γ-Hydroxybutyrate on the Relationship between Local Cerebral Glucose Utilization and Local Cerebral Blood Flow in the Rat Brain

1985 ◽  
Vol 5 (1) ◽  
pp. 58-64 ◽  
Author(s):  
W. Kuschinsky ◽  
S. Suda ◽  
L. Sokoloff
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Rat Brain ◽  
Glucose Utilization ◽  
Local Cerebral Blood Flow ◽  
Local Cerebral Glucose Utilization ◽  
Cerebral Glucose Utilization ◽  
Minor Degree ◽  
A Minor ◽  
The Relationship

The relationship between local cerebral glucose utilization (LCGU) and local CBF (LCBF) was examined during the action of γ-hydroxybutyrate (GHB) (900 mg/kg i.v.) in conscious rats. GHB induced discrepant effects on blood flow and metabolism. LCGU was markedly depressed in all structures examined, whereas LCBF was differently affected in that no related changes were observed. Global glucose utilization was markedly depressed (- 51%), whereas global blood flow was not significantly altered. The marked dissociation between the changes in global glucose utilization and global blood flow induced by GHB is reflected only to a minor degree in the local values inasmuch as the correlation between LCGU and LCBF was only slightly weakened and its heterogeneity was increased.

LOCAL CEREBRAL BLOOD FLOW DURING HIGH DOSE FENTANYL IN THE RAT

1982 ◽  
Vol 57 (3) ◽  
pp. A348-A348
Author(s):  
T. Maekawa ◽  
C. Tommasino ◽  
H. M. Shapiro
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Dose ◽  
Local Cerebral Blood Flow

Heterogeneity of local cerebral blood flow-PaCO2 sensitivity in neonatal dogs

1980 ◽  
Vol 49 (1) ◽  
pp. 113-118 ◽  
Author(s):  
H. M. Shapiro ◽  
J. H. Greenberg ◽  
K. V. Naughton ◽  
M. Reivich
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subcortical White Matter ◽  
Carbon Dioxide Tension ◽  
Reciprocal Relationship ◽  
Local Cerebral Blood Flow ◽  
Brain Areas ◽  
Co2 Sensitivity ◽  
Autoradiographic Technique ◽  
Cerebral Vascular Resistance

Local cerebral blood flow (1-CBF) sensitivity to changes in arterial carbon dioxide tension (PaCO2) was measured in nitrous oxide-anesthetized newborn puppies using a quantitative autoradiographic technique and [14C]antipyrine as a tracer. 1-CBF was determined in four experimental groups at PaCO2 levels of 22, 34, 48, and 65 Torr, respectively. All seven brain areas studied demonstrated 1-CBF sensitivity to altered PaCO2. There were no significant differences (P greater than 0.05) in three subcortical white matter regions (frontal, parietal, occipital) in either 1-CBF or 1-CBF-CO2 sensitivity. With the exception of the thalamus, a reciprocal relationship existed between changes in local cerebral vascular resistance and blood flow. In the thalamus, 1-CBF increased at a greater rate than the 1-CVR reduction. The results show that CBF is heterogeneous in different brain areas of the neonatal dog at normocapnia and that differences in 1-CBF-CO2 sensitivity exist.

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