Effect of hematocrit variations on cerebral blood flow and basilar artery diameter in vivo

1992 ◽  
Vol 262 (4) ◽  
pp. H949-H954 ◽  
Author(s):  
J. P. Muizelaar ◽  
G. J. Bouma ◽  
J. E. Levasseur ◽  
H. A. Kontos
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Basilar Artery ◽  
Cerebral Arteries ◽  
Blood Rheology ◽  
Inverse Correlation ◽  
Large Artery ◽  
Altered Blood ◽  
Reported Data

Despite observations that pial arterioles constrict with decreased blood viscosity or hemodilution, several investigators have found an inverse relationship between cerebral blood flow (CBF) and hematocrit (Hct) under physiological conditions. To investigate whether this is due to a dilation of the more proximal large cerebral arteries, in vivo responses of CBF and basilar artery to hemodilution and hemoconcentration were studied in 21 anesthetized normal cats, using a closed clival window model. An inverse correlation between Hct and CBF was found, but CBF responses were smaller than previously reported data suggest. Varying Hct between 60 and 120% of baseline caused CBF to vary between 140 and 90%, approximately. Moderate hemodilution was associated with a significant decrease (-4.4%) in basilar artery diameter (P less than 0.05), but other Hct manipulations had no consistent effect on basilar artery diameter. It is concluded that dilation of large cerebral arteries cannot account for the decreased cerebrovascular resistance following hemodilution but that a disproportionate reduction of in vivo viscosity must be responsible. Pial arteriolar constriction after hemodilution therefore probably reflects a normal autoregulatory adjustment of vasomotor tone to altered blood rheology, whereas changes in large artery caliber may serve to modulate microvascular pressure.

scholarly journals Amylin: Localization, Effects on Cerebral Arteries and on Local Cerebral Blood Flow in the Cat

2001 ◽  
Vol 1 ◽  
pp. 168-180 ◽  
Author(s):  
Lars Edvinsson ◽  
Peter J. Goadsby ◽  
Rolf Uddman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Vessels ◽  
Cerebral Arteries ◽  
In Vivo Studies ◽  
Cerebral Blood Vessels ◽  
Local Cerebral Blood Flow ◽  
Doppler Flowmetry

Amylin and adrenomedullin are two peptides structurally related to calcitonin gene-related peptide (CGRP). We studied the occurrence of amylin in trigeminal ganglia and cerebral blood vessels of the cat with immunocytochemistry and evaluated the role of amylin and adrenomedullin in the cerebral circulation by in vitro and in vivo pharmacology. Immunocytochemistry revealed that numerous nerve cell bodies in the trigeminal ganglion contained CGRP immunoreactivity (-ir); some of these also expressed amylin-ir but none adrenomedullin-ir. There were numerous nerve fibres surrounding cerebral blood vessels that contained CGRP-ir. Occasional fibres contained amylin-ir while we observed no adrenomedullin-ir in the vessel walls. With RT-PCR and Real-Time�PCR we revealed the presence of mRNA for calcitonin receptor-like receptor (CLRL) and receptor-activity-modifying proteins (RAMPs) in cat cerebral arteries. In vitro studies revealed that amylin, adrenomedullin, and CGRP relaxed ring segments of the cat middle cerebral artery. CGRP and amylin caused concentration-dependent relaxations at low concentrations of PGF2a-precontracted segment (with or without endothelium) whereas only at high concentration did adrenomedullin cause relaxation. CGRP8-37 blocked the CGRP and amylin induced relaxations in a parallel fashion. In vivo studies of amylin, adrenomedullin, and CGRP showed a brisk reproducible increase in local cerebral blood flow as examined using laser Doppler flowmetry applied to the cerebral cortex of the a-chloralose�anesthetized cat. The responses to amylin and CGRP were blocked by CGRP8-37. The studies suggest that there is a functional sub-set of amylin-containing trigeminal neurons which probably act via CGRP receptors.

scholarly journals Catechin prevents severe dyslipidemia-associated changes in wall biomechanics of cerebral arteries in LDLr−/−:hApoB+/+ mice and improves cerebral blood flow

2012 ◽  
Vol 302 (6) ◽  
pp. H1330-H1339 ◽  
Author(s):  
Virginie Bolduc ◽  
Edward Baraghis ◽  
Natacha Duquette ◽  
Nathalie Thorin-Trescases ◽  
Jean Lambert ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Endothelial Dysfunction ◽  
Cerebral Artery ◽  
Cerebral Arteries ◽  
Strain Curve ◽  
Cerebral Hypoperfusion ◽  
Wall Structure ◽  
Artery Wall

Endothelial dysfunction and oxidative stress contribute to the atherosclerotic process that includes stiffening of large peripheral arteries. In contrast, our laboratory previously reported a paradoxical increase in cerebrovascular compliance in LDLr−/−:hApoB+/+ atherosclerotic (ATX) mice ( 7 ). We hypothesized that prevention of cerebral artery endothelial dysfunction with a chronic dietary antioxidant intake would normalize the changes in cerebral artery wall structure and biomechanics and prevent the decline in basal cerebral blood flow associated with atherosclerosis. Three-month-old ATX mice were treated, or not, for 3 mo with the polyphenol (+)-catechin (CAT; 30 mg·kg−1·day−1) and compared with wild-type controls. In isolated, pressurized cerebral arteries from ATX mice, CAT prevented endothelial dysfunction (deterioration of endothelium-dependent, flow-mediated dilations; P < 0.05), the inward hypertrophic structural remodeling (increase in the wall-to-lumen ratio; P < 0.05), and the rise in cerebrovascular compliance (rightward shift of the stress-strain curve measured in passive conditions, reflecting mechanical properties of the arterial wall; P < 0.05). Doppler optical coherence tomography imaging in vivo confirmed these findings, showing that cerebral compliance was higher in ATX mice and normalized by CAT ( P < 0.05). CAT also prevented basal cerebral hypoperfusion in ATX mice ( P < 0.05). Active remodeling of the cerebrovascular wall in ATX mice was further suggested by the increase ( P < 0.05) in pro-metalloproteinase-9 activity, which was normalized by CAT. We conclude that, by preserving the endothelial function, a chronic treatment with CAT prevents the deleterious effect of severe dyslipidemia on cerebral artery wall structure and biomechanical properties, contributing to preserving resting cerebral blood flow.

Cerebral blood flow velocities in the anterior cerebral arteries and basilar artery in hydrocephalus before and after treatment

1990 ◽  
Vol 34 (6) ◽  
pp. 373-377 ◽  
Author(s):  
Shigeru Nishimaki ◽  
Hitoshi Yoda ◽  
Kazuo Seki ◽  
Tadashi Kawakami ◽  
Hiroshi Akamatsu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Basilar Artery ◽  
Cerebral Arteries ◽  
Before And After ◽  
Blood Flow Velocities ◽  
Flow Velocities

scholarly journals Changes in Cerebral Blood Flow after Erenumab Treatment in Good and Non-Responders—A Pilot Study of Migraine Patients

2021 ◽  
Vol 10 (11) ◽  
pp. 2523
Author(s):  
Magdalena Nowaczewska ◽  
Marcin Straburzyński ◽  
Grzegorz Meder ◽  
Wojciech Kaźmierczak
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Basilar Artery ◽  
Treatment Effectiveness ◽  
Medication Overuse ◽  
Medication Overuse Headache ◽  
Cerebral Arteries ◽  
Significant Negative Correlation ◽  
Lower Baseline ◽  
Baseline Values

Erenumab showed efficacy in migraine prevention, however we cannot identify which patients to treat by predicting efficacy response. The aim of this study was to compare changes in cerebral blood flow (CBF) reflected by transcranial Doppler (TCD) in erenumab good responders (GR) and non-responders, in order to identify a parameter that could predict the treatment response. In this study, migraineurs treated with erenumab underwent clinical and TCD evaluations before and 6 weeks after the treatment, including data on migraine type, monthly migraine days (MMD), medication overuse headache (MOH) presence, mean blood flow velocity (Vm) and pulsatility index (PI) in cerebral arteries (CA). GR were defined as reporting ≥50% reduction in MMD. Thirty women were enrolled, of mean age 40.53 years, 20 with chronic migraine, 14 with MOH, and 19 were GR. Baseline Vm values in right CA and basilar artery (BA) were significantly lower in GR as compared with non-responders. Vm values in all arteries significantly increased after the treatment as compared with corresponding baseline values, but only in GR. A significant negative correlation was observed between baseline Vm in right CA and treatment effectiveness. Baseline Vm in right CA and basilar artery is reduced in erenumab GR as compared with non-responders. This asymmetry normalizes after the treatment with significant Vm increase in CA which may reflect CBF increase in GR only. Lower baseline Vm in right CA may predict erenumab efficacy; however, these results should be replicated in a larger cohort.

scholarly journals Endothelium-Derived Relaxing Factor Inhibits Constrictor Responses of Large Cerebral Arteries to Serotonin

1992 ◽  
Vol 12 (3) ◽  
pp. 500-506 ◽  
Author(s):  
Frank M. Faraci ◽  
Donald D. Heistad
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Vascular Resistance ◽  
Cerebral Arteries ◽  
Large Arteries ◽  
Relaxing Factor ◽  
Endothelium Derived Relaxing Factor ◽  
Cerebral Vascular Resistance ◽  
Cerebral Vascular

Endothelium-derived relaxing factor [EDRF, nitric oxide (NO) or a NO-containing compound] influences basal tone of cerebral blood vessels and mediates vasodilation in response to several stimuli. It is not known whether EDRF also modulates responses to cerebral vasoconstrictor stimuli in vivo. Our goal was to determine whether formation of EDRF inhibits constrictor responses of large cerebral arteries to serotonin. We measured cerebral blood flow (microspheres) and pial microvascular pressure (servo null) in anesthetized rabbits and calculated resistance of large cerebral arteries. Responses to an inhibitor of NO formation, NG-nitro-l-arginine (l-NNA, 3 mg/kg i.v.), were examined. l-NNA produced an increase in resistance of large arteries and total cerebral vascular resistance of approximately 15% (p < 0.05 for both variables) and a small decrease in cerebral blood flow (35 ± 9 vs. 32 ± 7 ml min−1 100 g−1, mean ± SD, p < 0.05). Under control conditions, infusion of serotonin (10 μg kg−1 min−1, into the left atrium) produced an increase in resistance of large arteries. Following treatment with l-NNA, the change in resistance of large arteries in response to serotonin was increased more than twofold (0.20 ± 0.17 vs. 0.43 ± 0.21 mm Hg ml−1 min 100 g, p < 0.05). In contrast, l-NNA did not alter the increase in resistance of large arteries during hypocapnia. l-arginine inhibited the effects of l-NNA on baseline cerebral vascular resistance and on responses of large arteries to serotonin. Thus, formation of EDRF (NO) from l-arginine (a) has a modest influence on cerebral blood flow under basal conditions and (b) inhibits constriction of large cerebral arteries to serotonin, but not hypocapnia.

Effect of caffeine on theophyliine on cerebral blood flow response to brain activation: In vitro and in vivo studies

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S198-S198
Author(s):  
Joseph R Meno ◽  
Thien-son K Nguyen ◽  
Elise M Jensen ◽  
G Alexander West ◽  
Leonid Groysman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Activation ◽  
In Vivo Studies ◽  
Blood Flow Response ◽  
Flow Response

scholarly journals Transcranial Doppler Evaluation of the Cerebral Vasculature in Women Patients who Have Migraine with Aura

Pain Medicine ◽  
2020 ◽  
Vol 21 (11) ◽  
pp. 3012-3017
Author(s):  
Igor Petrušić ◽  
Ana Podgorac ◽  
Aleksandra Radojičić ◽  
Jasna Zidverc-Trajković
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Migraine With Aura ◽  
Transcranial Doppler ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Left And Right

Abstract Background Previous studies suggest that increased cerebrovascular reactivity might be a feature of patients who have migraine with aura (MwA). The correlation between the clinical presentation of migraine with aura and transcranial Doppler parameters remains unclear. Objective The main aim of this study was to explore cerebral blood flow, vascular resistance, and cerebrovascular reactivity in women MwA. Also, the relationships between hemodynamic conditions and aura characteristics are examined. Design Cross-sectional study. Setting Headache Center, Neurology Clinic, Clinical Center of Serbia. Subjects Fifty-four women MwA and 49 healthy controls (HCs). Methods Transcranial Doppler sonography examination was used to determine blood flow mean velocity (MV) and pulsatility index (PI), as well as breath-holding index (BHI), in 15 arterial segments comprising the circle of Willis. Results A total of 54 women MwA and 49 HCs were studied. The PIs of all segments of the left and right middle cerebral arteries and the left and right anterior cerebral arteries were significantly higher in MwA with regards to HCs. Also, both the left and right BHIs were significantly higher in MwA than HCs. In addition, MVs of the right vertebral artery and the first segment of the basilar artery were significantly lower in MwA than HCs. Longer duration of migraine aura showed a weak negative correlation with the PI of the left posterior cerebral artery. Conclusions Our findings suggest increased vessel pulsatility, abnormal cerebrovascular reactivity, and decreased cerebral blood flow velocity in several arterial segments of the Willis circle in women MwA.

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