A Note on the Ammonia and Glutamine Content of the Cerebrospinal Fluid

1949 ◽  
Vol 95 (398) ◽  
pp. 148-152 ◽  
Author(s):  
D. Richter ◽  
R.M.C. Dawson ◽  
Linford Rees
Keyword(s):  
Cerebrospinal Fluid ◽  
Glutamic Acid ◽  
Ammonium Chloride ◽  
Inhibitory Action ◽  
Enzyme System ◽  
Toxic Action ◽  
Irritant Action ◽  
The Brain

Tashiro (1922) showed that the isolated frog nerve liberates ammonia on stimulation, and Richter and Dawson (1948) have recently found that ammonia is liberated on stimulation by the brain. Ammonia is very toxic to the brain, on which it has an irritant action; but the brain may be protected to some extent by the enzyme system described by Krebs (1935), which can detoxicate ammonia by combination with glutamic acid to form glutamine. Sapirstein (1943) obtained evidence that this system is active in vivo by showing that glutamic acid increases the resistance of animals to convulsions produced by injecting ammonium chloride. The toxic action of ammonia on the brain is also of interest in connection with the view that it may be concerned in certain forms of epilepsy (Harris, 1945). This view is supported by the observations of Price, Waelsch and Putnam (1943) on the inhibitory action of glutamic acid on petit mal attacks.

scholarly journals The Potential Roles of Blood–Brain Barrier and Blood–Cerebrospinal Fluid Barrier in Maintaining Brain Manganese Homeostasis

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1833
Author(s):  
Shannon Morgan McCabe ◽  
Ningning Zhao
Keyword(s):  
Cerebrospinal Fluid ◽  
Blood Brain Barrier ◽  
Blood Circulation ◽  
Critical Role ◽  
Systemic Circulation ◽  
Brain Parenchyma ◽  
Brain Barrier ◽  
Blood Brain ◽  
The Brain

Manganese (Mn) is a trace nutrient necessary for life but becomes neurotoxic at high concentrations in the brain. The brain is a “privileged” organ that is separated from systemic blood circulation mainly by two barriers. Endothelial cells within the brain form tight junctions and act as the blood–brain barrier (BBB), which physically separates circulating blood from the brain parenchyma. Between the blood and the cerebrospinal fluid (CSF) is the choroid plexus (CP), which is a tissue that acts as the blood–CSF barrier (BCB). Pharmaceuticals, proteins, and metals in the systemic circulation are unable to reach the brain and spinal cord unless transported through either of the two brain barriers. The BBB and the BCB consist of tightly connected cells that fulfill the critical role of neuroprotection and control the exchange of materials between the brain environment and blood circulation. Many recent publications provide insights into Mn transport in vivo or in cell models. In this review, we will focus on the current research regarding Mn metabolism in the brain and discuss the potential roles of the BBB and BCB in maintaining brain Mn homeostasis.

scholarly journals Signs of Myelin Impairment in Cerebrospinal Fluid After Osmotic Opening of the Blood-Brain Barrier in Rats

2015 ◽  
pp. S603-S608 ◽  
Author(s):  
P. KOZLER ◽  
O. SOBEK ◽  
J. POKORNÝ
Keyword(s):  
Cerebrospinal Fluid ◽  
Myelin Basic Protein ◽  
Blood Brain Barrier ◽  
Basic Protein ◽  
Brain Barrier ◽  
In Vivo Experiment ◽  
Blood Brain ◽  
Significant Difference ◽  
The Brain

A number of clinical neurological pathologies are associated with increased permeability of the blood brain barrier (BBB). Induced changes of the homeostatic mechanisms in the brain microenvironment lead among others to cellular changes in the CNS. The question was whether some of these changes can be induced by osmotic opening of BBB in an in vivo experiment and whether they can be detected in cerebrospinal fluid (CSF). CSF was taken via the suboccipital puncture from 10 healthy rats and six rats after the osmotic opening of the BBB. In all 16 animals, concentration of myelin basic protein (MBP ng/ml), Neuron-specific enolase (NSE ng/ml) and Tau-protein (Tau pg/ml) were determined in CSF by ELISA. Values in both groups were statistically evaluated. Significant difference between the control and experimental group was revealed only for the concentration of myelin basic protein (p<0.01). The presented results indicate that osmotic opening of the BBB in vivo experiment without the presence of other pathological conditions of the brain leads to a damage of myelin, without impairment of neurons or their axons.

scholarly journals Human CNS barrier-forming organoids with cerebrospinal fluid production

Science ◽  
2020 ◽  
Vol 369 (6500) ◽  
pp. eaaz5626 ◽  
Author(s):  
Laura Pellegrini ◽  
Claudia Bonfio ◽  
Jessica Chadwick ◽  
Farida Begum ◽  
Mark Skehel ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Fluid Secretion ◽  
Fluid Production ◽  
New Compounds ◽  
High Degree ◽  
The Brain ◽  
Degree Of Similarity ◽  
By Products

Cerebrospinal fluid (CSF) is a vital liquid, providing nutrients and signaling molecules and clearing out toxic by-products from the brain. The CSF is produced by the choroid plexus (ChP), a protective epithelial barrier that also prevents free entry of toxic molecules or drugs from the blood. Here, we establish human ChP organoids with a selective barrier and CSF-like fluid secretion in self-contained compartments. We show that this in vitro barrier exhibits the same selectivity to small molecules as the ChP in vivo and that ChP-CSF organoids can predict central nervous system (CNS) permeability of new compounds. The transcriptomic and proteomic signatures of ChP-CSF organoids reveal a high degree of similarity to the ChP in vivo. Finally, the intersection of single-cell transcriptomics and proteomic analysis uncovers key human CSF components produced by previously unidentified specialized epithelial subtypes.

In Vivo Microdialysis in Mice Captures Changes in Alzheimer’s Disease Cerebrospinal Fluid Biomarkers Consistent with Developing Pathology

2021 ◽  
pp. 1-14
Author(s):  
Christiana Bjorkli ◽  
Claire Louet ◽  
Trude Helen Flo ◽  
Mary Hemler ◽  
Axel Sandvig ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebrospinal Fluid ◽  
Mouse Model ◽  
Amyloid Β ◽  
Csf Biomarkers ◽  
Intracerebral Microdialysis ◽  
Preclinical Models ◽  
The Brain

Background: Preclinical models of Alzheimer’s disease (AD) can provide valuable insights into the onset and progression of the disease, such as changes in concentrations of amyloid-β (Aβ) and tau in cerebrospinal fluid (CSF). However, such models are currently underutilized due to limited advancement in techniques that allow for longitudinal CSF monitoring. Objective: An elegant way to understand the biochemical environment in the diseased brain is intracerebral microdialysis, a method that has until now been limited to short-term observations, or snapshots, of the brain microenvironment. Here we draw upon patient-based findings to characterize CSF biomarkers in a commonly used preclinical mouse model for AD. Methods: Our modified push-pull microdialysis method was first validated ex vivo with human CSF samples, and then in vivo in an AD mouse model, permitting assessment of dynamic changes of CSF Aβ and tau and allowing for better translational understanding of CSF biomarkers. Results: We demonstrate that CSF biomarker changes in preclinical models capture what is observed in the brain; with a decrease in CSF Aβ observed when plaques are deposited, and an increase in CSF tau once tau pathology is present in the brain parenchyma. We found that a high molecular weight cut-off membrane allowed for simultaneous sampling of Aβ and tau, comparable to CSF collection by lumbar puncture in patients. Conclusion: Our approach can further advance AD and other neurodegenerative research by following evolving neuropathology along the disease cascade via consecutive sampling from the same animal and can additionally be used to administer pharmaceutical compounds and assess their efficacy (Bjorkli, unpublished data).

scholarly journals Cerebrospinal Fluid Efflux Through Dynamic Paracellular Pores on Venule as a Missing Piece for the Image of Brain Drainage System

2021 ◽  
Author(s):  
Yaqiong Dong ◽  
Ting Xu ◽  
Lan Yuan ◽  
Yahan Wang ◽  
Siwang Yu ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Laser Scanning ◽  
Vascular Endothelial Cells ◽  
Drainage System ◽  
Fluorescein Isothiocyanate ◽  
Blood Pool ◽  
Confocal Laser ◽  
Perivascular Spaces ◽  
The Brain

Abstract Background: The glymphatic system has been considered to contribute to a larger portion of parenchyma waste clearance and related to pathogenesis of many neural degenerative diseases such as the Alzheimer’s disease (AD). However, up to date, the key route for the efflux from perivascular spaces to the blood pool remains a mystery.Methods: BBB-impermeable fluorescent lanthanide probes of different size were first applied as cerebrospinal fluid (CSF)/interstitial fluid (ISF) tracers to quantitatively clarify the relative importance of different pathways to drain CSF/ISF solutes. The in vivo dynamic flows of subarachnoid CSF labeled with fluorescein isothiocyanate-dextran (4 kDa) tracers along brain blood vessels were observed under a two-photon confocal laser scanning microscope. Results: Three phasic process for the brain drainage was observed, in which the rapid efflux of ISF solutes with a time constant close to the CSF oscillation during sleep appeals for new routes from perivenuous spaces to the blood pool. Careful observation on the dynamic efflux in vivo revealed a novel drainage pathway in which CSF molecules converge into the bloodstream directly through dynamic trumpet-like pores (basolateral f＜8 μm; apical f＜2 μm) on the wall of brain venule in mice. Zn2+, an inducer of reconstruction of the tight junctions (TJs) in vascular endothelial cells, could facilitate the brain clearance of macromolecular ISF solutes. Deficit clearance of Aβ through the asymmetric pores on venule potentially causing perivascular space dilation was observed on the AD model mice.Conclusions: The novel asymmetric pore path through reconstruction of endothelial TJs on the wall of venule shall provide a key piece for ISF solutes to drainage from brain in very rapid pathway. The update image would help to understand the structure and the regulation of glymphatic clearance of brain metabolites such as Aβ in search for the solutions of neurodegenerative diseases.

scholarly journals Hydraulic resistance of perivascular spaces in the brain

2019 ◽  
Author(s):  
Jeffrey Tithof ◽  
Douglas H. Kelley ◽  
Humberto Mestre ◽  
Maiken Nedergaard ◽  
John H. Thomas
Keyword(s):  
Cerebrospinal Fluid ◽  
Blood Vessels ◽  
Hydraulic Resistance ◽  
Perivascular Spaces ◽  
Navier Stokes Equation ◽  
Pial Arteries ◽  
Cross Sectional ◽  
Annular Channels ◽  
The Brain

AbstractBackgroundPerivascular spaces (PVSs) are annular channels that surround blood vessels and carry cerebrospinal fluid through the brain, sweeping away metabolic waste. In vivo observations reveal that they are not concentric, circular annuli, however: the outer boundaries are often oblate, and the blood vessels that form the inner boundaries are often offset from the central axis.MethodsWe model PVS cross-sections as circles surrounded by ellipses and vary the radii of the circles, major and minor axes of the ellipses, and two-dimensional eccentricities of the circles with respect to the ellipses. For each shape, we solve the governing Navier-Stokes equation to determine the velocity profile for steady laminar flow and then compute the corresponding hydraulic resistance.ResultsWe find that the observed shapes of PVSs have lower hydraulic resistance than concentric, circular annuli of the same size, and therefore allow faster, more efficient flow of cerebrospinal fluid. We find that the minimum hydraulic resistance (and therefore maximum flow rate) for a given PVS cross-sectional area occurs when the ellipse is elongated and intersects the circle, dividing the PVS into two lobes, as is common around pial arteries. We also find that if both the inner and outer boundaries are nearly circular, the minimum hydraulic resistance occurs when the eccentricity is large, as is common around penetrating arteries.ConclusionsThe concentric circular annulus assumed in recent studies is not a good model of the shape of actual PVSs observed in vivo, and it greatly overestimates the hydraulic resistance of the PVS. Our parameterization can be used to incorporate more realistic resistances into hydraulic network models of flow of cerebrospinal fluid in the brain. Our results demonstrate that actual shapes observed in vivo are nearly optimal, in the sense of offering the least hydraulic resistance. This optimization may well represent an evolutionary adaptation that maximizes clearance of metabolic waste from the brain.

scholarly journals Leukocyte Recruitment in the Cerebrospinal Fluid of Mice with Experimental Meningitis Is Inhibited by an Antibody to Junctional Adhesion Molecule (Jam)

1999 ◽  
Vol 190 (9) ◽  
pp. 1351-1356 ◽  
Author(s):  
Aldo Del Maschio ◽  
Ada De Luigi ◽  
Ines Martin-Padura ◽  
Manfred Brockhaus ◽  
Tamas Bartfai ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Adhesion Molecule ◽  
Brain Parenchyma ◽  
Immunoglobulin Superfamily ◽  
Leukocyte Transmigration ◽  
Leukocyte Accumulation ◽  
Brain Barrier Permeability ◽  
The Brain

The mechanisms that govern leukocyte transmigration through the endothelium are not yet fully defined. Junctional adhesion molecule (JAM) is a newly cloned member of the immunoglobulin superfamily which is selectively concentrated at tight junctions of endothelial and epithelial cells. A blocking monoclonal antibody (BV11 mAb) directed to JAM was able to inhibit monocyte transmigration through endothelial cells in in vitro and in vivo chemotaxis assays. In this study, we report that BV11 administration was able to attenuate cytokine-induced meningitis in mice. The intravenous injection of BV11 mAb significantly inhibited leukocyte accumulation in the cerebrospinal fluid and infiltration in the brain parenchyma. Blood–brain barrier permeability was also reduced by the mAb. We conclude that JAM may be a new target in limiting the inflammatory response that accompanies meningitis.

scholarly journals Cerebrospinal fluid drainage kinetics across the cribriform plate are reduced with aging

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Molly Brady ◽  
Akib Rahman ◽  
Abigail Combs ◽  
Chethana Venkatraman ◽  
R. Tristan Kasper ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Ex Vivo ◽  
Cribriform Plate ◽  
Cervical Lymph Nodes ◽  
Spinal Subarachnoid Space ◽  
Ex Vivo Tissues ◽  
The Brain

Abstract Background Continuous circulation and drainage of cerebrospinal fluid (CSF) are essential for the elimination of CSF-borne metabolic products and neuronal function. While multiple CSF drainage pathways have been identified, the significance of each to normal drainage and whether there are differential changes at CSF outflow regions in the aging brain are unclear. Methods Dynamic in vivo imaging of near infrared fluorescently-labeled albumin was used to simultaneously visualize the flow of CSF at outflow regions on the dorsal side (transcranial and -spinal) of the central nervous system. This was followed by kinetic analysis, which included the elimination rate constants for these regions. In addition, tracer distribution in ex vivo tissues were assessed, including the nasal/cribriform region, dorsal and ventral surfaces of the brain, spinal cord, cranial dura, skull base, optic and trigeminal nerves and cervical lymph nodes. Results Based on the in vivo data, there was evidence of CSF elimination, as determined by the rate of clearance, from the nasal route across the cribriform plate and spinal subarachnoid space, but not from the dorsal dural regions. Using ex vivo tissue samples, the presence of tracer was confirmed in the cribriform area and olfactory regions, around pial blood vessels, spinal subarachnoid space, spinal cord and cervical lymph nodes but not for the dorsal dura, skull base or the other cranial nerves. Also, ex vivo tissues showed retention of tracer along brain fissures and regions associated with cisterns on the brain surfaces, but not in the brain parenchyma. Aging reduced CSF elimination across the cribriform plate but not that from the spinal SAS nor retention on the brain surfaces. Conclusions Collectively, these data show that the main CSF outflow sites were the nasal region across the cribriform plate and from the spinal regions in mice. In young adult mice, the contribution of the nasal and cribriform route to outflow was much higher than from the spinal regions. In older mice, the contribution of the nasal route to CSF outflow was reduced significantly but not for the spinal routes. This kinetic approach may have significance in determining early changes in CSF drainage in neurological disorder, age-related cognitive decline and brain diseases.

scholarly journals Kinetic Profile of the Transcriptome Changes Induced in the Choroid Plexus by Peripheral Inflammation

2009 ◽  
Vol 29 (5) ◽  
pp. 921-932 ◽  
Author(s):  
Fernanda Marques ◽  
João C Sousa ◽  
Giovanni Coppola ◽  
Ana M Falcao ◽  
Ana João Rodrigues ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Choroid Plexus ◽  
Acute Phase ◽  
Acute Phase Proteins ◽  
Brain Parenchyma ◽  
Matrix Remodeling ◽  
Choroid Plexus Epithelial Cell ◽  
Blood Concentrations ◽  
The Brain

The choroid plexus, being part of the blood-brain barriers and responsible for the production of cerebrospinal fluid, is ideally positioned to transmit signals into and out of the brain. This study, using microarray analysis, shows that the mouse choroid plexus displays an acute-phase response after an inflammatory stimulus induced in the periphery by lipopolysaccharide (LPS). Remarkably, the response is specific to a restricted number of genes (out of a total of 24,000 genes analyzed, 252 are up-regulated and 173 are down-regulated) and transient, as it returns to basal conditions within 72 h. The up-regulated genes cluster into families implicated in immune-mediated cascades and in extracellular matrix remodeling, whereas those down-regulated participate in maintenance of the barrier function. Importantly, several acute-phase proteins, whose blood concentrations rise in response to inflammation, may contribute to the effects observed in vivo after LPS injection, as suggested by the differential response of primary choroid plexus epithelial cell cultures to LPS alone or to serum collected from animals exposed to LPS. By modulating the composition of the cerebrospinal fluid, which will ultimately influence the brain parenchyma, the choroid plexus response to inflammation may be of relevance in brain homeostasis in health and disease.

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