scholarly journals The Cerebral Circulation During Pregnancy: Adapting to Preserve Normalcy

Physiology ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Abbie C. Johnson ◽  
Marilyn J. Cipolla
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Cerebral Circulation ◽  
Cerebral Arteries ◽  
Structure And Function ◽  
Cerebral Blood Flow Autoregulation ◽  
And Function ◽  
The Brain ◽  
Brain Homeostasis

The adaptation of the brain and cerebral circulation to pregnancy are unique compared with other organs and circulatory systems, ultimately functioning to maintain brain homeostasis. In this review, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier, and changes in the structure and function of cerebral arteries and arterioles, hemodynamics, and cerebral blood flow autoregulation.

Effect of sympathetic nerves on cerebral vessels during seizures

1979 ◽  
Vol 237 (2) ◽  
pp. H178-H184 ◽  
Author(s):  
S. M. Mueller ◽  
D. D. Heistad ◽  
M. L. Marcus
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Sympathetic Nerve Activity ◽  
Sympathetic Nerves ◽  
Brain Barrier ◽  
Blood Brain ◽  
Brain Barrier Permeability ◽  
Cervical Sympathetic ◽  
The Brain

The purpose of this study was to determine the effect of activation of sympathetic pathways during seizures on cerebral blood flow and integrity of the blood-brain barrier. We measured cerebral blood flow with microspheres and disruption of the blood-brain barrier with labeled albumin in cats. One cerebral hemisphere was denervated by cutting the superior cervical sympathetic trunk on one side. During bicuculline-induced seizures, superior cervical sympathetic nerve activity increased about threefold. Blood flow to the innervated hemibrain was significantly lower than flow to denervated hemibrain. However, in relation to the total increase in flow, this effect of nerves was minor. Blood-brain barrier permeability increased about sixfold during seizures, but there was no difference between the innervated and denervated sides of the brain. We conclude that sympathetic nerves attenuate the increase in cerebral blood flow during seizures, despite the increase in metabolism, but this effect is small. Activation of sympathetic nerves does not reduce disruption of the blood-brain barrier during seizures.

scholarly journals Blood—Brain Barrier Transport of Butanol and Water Relative to N-Isopropyl-p-Iodoamphetamine as the Internal Reference

1985 ◽  
Vol 5 (2) ◽  
pp. 275-281 ◽  
Author(s):  
William M. Pardridge ◽  
Gary Fierer
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Internal Reference ◽  
Diffusion Restriction ◽  
Blood Brain ◽  
Anesthetized Rats ◽  
Rat Forebrain ◽  
The Brain

The literature regarding the blood–brain barrier (BBB) transport of butanol is conflicting as studies report both incomplete and complete extraction of butanol by the brain. In this work the BBB transport of both [14C]butanol and [3H]water was studied using the carotid injection technique in conscious and in ketamine- or pentobarbital-anesthetized rats employing N-isopropyl- p-[125I]iodoamphetamine ([125I]IMP) as the internal reference and as a fluid microsphere. The three isotopes (3H, 125I, 14C) were conveniently counted simultaneously in a liquid scintillation spectrometer. IMP is essentially completely sequestered by the brain for at least 1 min in conscious rats and for 2 min in anesthetized animals. Butanol extraction by rat forebrain is not flow limited but ranges between 77 ± 1 and 87 ± 1% for the three conditions. The incomplete extraction of butanol by the forebrain is due to diffusion restriction of butanol clearance in some regions (frontal cortex, colliculi) but not in others (caudate, hippocampus, olfactory bulb). The permeability-surface area product/cerebral blood flow ratio of butanol and water in rat forebrain remains relatively constant, 1.7 ± 0.2 and 1.0 ± 0.1, respectively, despite a twofold increase in cerebral blood flow in conscious relative to pentobarbital-anesthetized rats. The absence of an inverse relationship between flow and butanol or water extraction is consistent with capillary recruitment being the principal mechanism underlying changes in cerebral blood flow in anesthesia. The diffusion restriction of BBB transport of butanol in some regions, but not in others, necessitates a careful regional analysis of BBB permeability to butanol prior to usage of this compound as a cerebral blood flow marker.

Selected Contribution: Effects of aging on cerebrovascular tone and [Ca2+]i

2003 ◽  
Vol 95 (4) ◽  
pp. 1746-1754 ◽  
Author(s):  
Greg G. Geary ◽  
John N. Buchholz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Artery ◽  
Cerebral Arteries ◽  
No Synthase ◽  
The Other ◽  
Intraluminal Pressure ◽  
Age Dependent ◽  
Old Rats ◽  
Cerebral Blood Flow Autoregulation

The lower limits of cerebral blood flow autoregulation shift toward high pressures in aged compared with young rats. Intraluminal pressure stimulates contractile mechanisms in cerebral arteries that might, in part, cause an age-dependent shift in autoregulation. The present project tested two hypotheses. First, cerebral artery tone is greater in isolated arteries from aged compared with mature adult rats. Second, aging decreases the modulatory effect of endothelium-derived nitric oxide (NO) and increases vascular smooth muscle Ca2+ sensitivity. Isolated segments of middle cerebral arteries from male 6-, 12-, 20-, and 24-mo-old Fischer 344 rats were cannulated and loaded with fura-2. Diameter and Ca2+ responses to increasing pressure were measured in HEPES, during NO synthase inhibition [ NG-nitro-l-arginine methyl ester (l-NAME)], and after removal of the endothelium. Cerebral artery tone (with endothelium) increased with age. Only at the lowest pressure (20 and 40 mmHg) was intracellular Ca2+ concentration ([Ca2+]i) greater in arteries from 24-mo-old rats compared with the other age groups. l-NAME-sensitive constriction increased significantly in arteries from 6- to 20-mo-old rats but declined significantly thereafter in arteries from 24-mo-old rats. [Ca2+]i was less in arteries from 24-mo-old rats compared with the other groups after treatment with l-NAME. Another endothelial-derived factor, insensitive to l-NAME, also decreased significantly with age. For example, at 60 mmHg, the l-NAME-insensitive constriction decreased from 47 ± 10, 42 ± 5, 21 ± 2, and 3 ± 1 μm in 6-, 12-, 20-, and 24-mo-old rats, respectively. Our data suggest that aging alters cerebral artery tone and [Ca2+]i responses through endothelial-derived NO synthase-sensitive and -insensitive mechanisms. The combined effect of greater cerebral artery tone with less endothelium-dependent modulation may in part contribute to the age-dependent shift in cerebral blood flow autoregulation.

scholarly journals Impaired myogenic response and autoregulation of cerebral blood flow is rescued in CYP4A1 transgenic Dahl salt-sensitive rat

2015 ◽  
Vol 308 (5) ◽  
pp. R379-R390 ◽  
Author(s):  
Fan Fan ◽  
Aron M. Geurts ◽  
Sydney R. Murphy ◽  
Mallikarjuna R. Pabbidi ◽  
Howard J. Jacob ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Arteries ◽  
Cerebral Injury ◽  
Transgenic Rat ◽  
Myogenic Response ◽  
Cerebral Vasculature ◽  
Synthesis Inhibitor ◽  
Middle Cerebral Arteries ◽  
The Brain

We have reported that a reduction in renal production of 20-HETE contributes to development of hypertension in Dahl salt-sensitive (SS) rats. The present study examined whether 20-HETE production is also reduced in the cerebral vasculature of SS rats and whether this impairs the myogenic response and autoregulation of cerebral blood flow (CBF). The production of 20-HETE, the myogenic response of middle cerebral arteries (MCA), and autoregulation of CBF were compared in SS, SS-5BN rats and a newly generated CYP4A1 transgenic rat. 20-HETE production was 6-fold higher in cerebral arteries of CYP4A1 and SS-5BN than in SS rats. The diameter of the MCA decreased to 70 ± 3% to 65 ± 6% in CYP4A1 and SS-5BN rats when pressure was increased from 40 to 140 mmHg. In contrast, the myogenic response of MCA isolated from SS rats did not constrict. Administration of a 20-HETE synthesis inhibitor, HET0016, abolished the myogenic response of MCA in CYP4A1 and SS-5BN rats but had no effect in SS rats. Autoregulation of CBF was impaired in SS rats compared with CYP4A1 and SS-5BN rats. Blood-brain barrier leakage was 5-fold higher in the brain of SS rats than in SS-5BN and SS.CYP4A1 rats. These findings indicate that a genetic deficiency in the formation of 20-HETE contributes to an impaired myogenic response in MCA and autoregulation of CBF in SS rats and this may contribute to vascular remodeling and cerebral injury following the onset of hypertension.

scholarly journals Peculiarities of cerebral blood flow in patients with chronic diffuse liver diseases of viral etiology

2014 ◽  
Vol 95 (6) ◽  
pp. 859-865 ◽  
Author(s):  
T S Morozova ◽  
I F Grishina ◽  
I A Gurikova
Keyword(s):  
Blood Flow ◽  
Liver Cirrhosis ◽  
Cerebral Blood Flow ◽  
Liver Diseases ◽  
Vascular System ◽  
Cerebral Arteries ◽  
Vascular Wall ◽  
Viral Etiology ◽  
The Brain ◽  
Diffuse Liver Diseases

Aim. To study the features of cerebral blood flow at different structural and functional levels of the brain vascular system in patients with chronic hepatitis and cirrhosis of viral etiology. Methods. A comprehensive ultrasound examination of the brain vascular system using an algorithm of cerebral arterial and venous blood flow examination based on the concept of the brain vascular system construction considering five structural and functional levels was performed in 65 chronic viral hepatitis patients and 61 patients with liver cirrhosis of viral etiology. The examination of the main brain arteries was performed using duplex scanning ultrasound SSD-5500 scanner («Aloka», Japan) with 5-12 MHz linear transducers. Examination of intracranial vessels was performed by transcranial color duplex scanning using ultrasonic SSD-5500 and «Sonoline G60» scanners («Siemens», Germany) with linear and phased 2.1-2.5 MHz transducers. Control group consisted of 50 healthy persons. Results. Remodeling of the cerebral arteries: the expansion of the lumen of the main cerebral vessels, reduction of blood flow in the carotid and middle cerebral arteries, decreased elasticity and increased vascular wall rigidity and, as a consequence, a change in vascular resistance and cerebral blood flow disturbance occurs in patients with chronic viral liver diseases. Identified changes of blood flow parameters at all levels of structural and functional brain perfusion indicate the presence of cerebral microangiopathy and arteriopathy based on the development of arteriosclerosis of main arteries and all penetrating arteries and arterioles in patients with chronic diffuse liver diseases. Conclusion. Adaptive remodeling of the vascular wall of the main cerebral arteries which provides an adequate regulatory response is found in patients with hepatitis B and C-associated liver cirrhosis. The reduction of blood supply to the brain, depletion of functional vascular reserve and development of intracranial venous circulatory distress are seen in patients with liver cirrhosis associated with viral hepatitis.

scholarly journals Diagnostic and prognostic potential of non-invasive assessment of cerebral blood flow autoregulation

2015 ◽  
Vol 14 (1) ◽  
pp. 4-14
Author(s):  
V. B. Semenyutin ◽  
V. A. Aliev ◽  
V. P. Bersnev ◽  
A. . Patzak ◽  
G. K. Panuntsev ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
Cerebral Arteries ◽  
Systemic Blood Pressure ◽  
Communicating Hydrocephalus ◽  
Non Invasive ◽  
Pathological Conditions ◽  
Neurosurgical Patients ◽  
Cerebral Blood Flow Autoregulation

Purpose. To study the potential of non-invasive assessment of cerebral blood flow autoregulation (CA) using cross-spectral analysis of slow dopplerographic patterns. Materials and methods. The study involved 40 healthy volunteers and 228 patients with different neurosurgical pathology: cerebral aneurysm - 50 cases, arteriovenous malformation - 52, traumatic brain injury - 61, communicating hydrocephalus - 24, parasagittal meningioma - 20, stenosis and thrombosis of the carotid arteries - 21. Blood flow velocity (BFV) in middle cerebral arteries was monitored using Multi Dop X (DWL, Germany), systemic blood pressure (BP) - noninvasively with Finapres (Ohmeda 2100 USA) within 4 minutes. CA was assessed by calculating the phase shift (PSM) between spontaneous slow oscillations of BP and BFV within the range of systemic Mayer waves (80-120 mHz) and amplitude of intracranial B-waves of BFV (AB) within the range from 8 to 50 mHz). Results and discussion. CA demonstrated different patterns in neurosurgical patients and varied from normal autoregulation to its complete absence. This indicates the degree of compensation of cerebral hemodynamics in pathological conditions such as intracranial hypertension, vasospasm, traumatic edema, ischemia, abnormal arteriovenous shunting. On the basis of perioperative evaluation of PSM and AB, the predictors of efficacy and outcome have been identified in patients with cerebral aneurysms in an acute period of hemorrhage, severe brain injury, cerebral arteriovenous malformations and communicating hydrocephalus. Conclusions. Analysis of slow-wave dopplerographic patterns of BFV in intracranial cerebral arteries and BP is informative, adequate, safe non-invasive way to assess CA in normal and pathological conditions. Perioperative assessment of these patterns can be used to predict the effectiveness of treatment in patients with different neurosurgical pathology.

scholarly journals Cerebral arteriolar structure and function in pinealectomized rats

2001 ◽  
Vol 281 (4) ◽  
pp. H1476-H1480 ◽  
Author(s):  
Olivier Régrigny ◽  
François Dupuis ◽  
Jeffrey Atkinson ◽  
Patrick Limiñana ◽  
Elizabeth Scalbert ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Wistar Rats ◽  
Structure And Function ◽  
Internal Diameter ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cranial Window ◽  
Arteriolar Wall ◽  
And Function

We examined cerebral arteriolar structure and autoregulation of cerebral blood flow (CBF) in control ( n = 8), sham-operated ( n = 8), pinealectomized ( n = 10), and pinealectomized plus melatonin-treated (0.51 ± 0.01 mg · kg−1 · day−1 in drinking water, n = 9) young Wistar rats. The lower limit of CBF autoregulation (LLCBF) was determined by measurement of CBF (in arbitrary units, laser Doppler) during stepwise hypotensive hemorrhage; the arteriolar internal diameter (ID; in μm, cranial window) was also measured. Measurements of ID were repeated during a second stepwise hypotension after smooth muscle cell deactivation (67 mmol/l EDTA). The cross-sectional area (CSA) was measured by histometry. CSA and EDTA-induced vasodilatation decreased after pinealectomy (517 ± 21 vs. 819 ± 40 μm2 in sham and 829 ± 55 μm2 in control, P < 0.05, and 81 ± 4 vs. 102 ± 5 μm in sham and 104 ± 4 μm in control, P < 0.05, respectively) and were restored by melatonin (924 ± 39 μm2 and 102 ± 5 μm, respectively). These results suggest that melatonin deprival makes the arteriolar wall thinner and stiffer. However, these changes had little effect on LLCBF. In conclusion, pinealectomy of young rats induces atrophy and decreases distensibility of the cerebral arteriolar wall; these effects are prevented by melatonin. They do not modify LLCBF.

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