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Szczygielski J, Kopańska M, Wysocka A, Oertel J. Cerebral Microcirculation, Perivascular Unit, and Glymphatic System: Role of Aquaporin-4 as the Gatekeeper for Water Homeostasis. Front Neurol 2021; 12:767470. [PMID: 34966347 PMCID: PMC8710539 DOI: 10.3389/fneur.2021.767470] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022] Open
Abstract
In the past, water homeostasis of the brain was understood as a certain quantitative equilibrium of water content between intravascular, interstitial, and intracellular spaces governed mostly by hydrostatic effects i.e., strictly by physical laws. The recent achievements in molecular bioscience have led to substantial changes in this regard. Some new concepts elaborate the idea that all compartments involved in cerebral fluid homeostasis create a functional continuum with an active and precise regulation of fluid exchange between them rather than only serving as separate fluid receptacles with mere passive diffusion mechanisms, based on hydrostatic pressure. According to these concepts, aquaporin-4 (AQP4) plays the central role in cerebral fluid homeostasis, acting as a water channel protein. The AQP4 not only enables water permeability through the blood-brain barrier but also regulates water exchange between perivascular spaces and the rest of the glymphatic system, described as pan-cerebral fluid pathway interlacing macroscopic cerebrospinal fluid (CSF) spaces with the interstitial fluid of brain tissue. With regards to this, AQP4 makes water shift strongly dependent on active processes including changes in cerebral microcirculation and autoregulation of brain vessels capacity. In this paper, the role of the AQP4 as the gatekeeper, regulating the water exchange between intracellular space, glymphatic system (including the so-called neurovascular units), and intravascular compartment is reviewed. In addition, the new concepts of brain edema as a misbalance in water homeostasis are critically appraised based on the newly described role of AQP4 for fluid permeation. Finally, the relevance of these hypotheses for clinical conditions (including brain trauma and stroke) and for both new and old therapy concepts are analyzed.
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Affiliation(s)
- Jacek Szczygielski
- Department of Neurosurgery, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland.,Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Marta Kopańska
- Department of Pathophysiology, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland
| | - Anna Wysocka
- Chair of Internal Medicine and Department of Internal Medicine in Nursing, Faculty of Health Sciences, Medical University of Lublin, Lublin, Poland
| | - Joachim Oertel
- Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
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Su CK, Ho CC. Online profiling of living rat brain extracellular pH using a pH-Dependent solid phase extraction scheme coupled with microdialysis sampling and inductively coupled plasma mass spectrometry. Anal Chim Acta 2019; 1055:36-43. [DOI: 10.1016/j.aca.2018.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 12/07/2018] [Accepted: 12/09/2018] [Indexed: 01/14/2023]
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Su CK, Yen SC, Li TW, Sun YC. Enzyme-Immobilized 3D-Printed Reactors for Online Monitoring of Rat Brain Extracellular Glucose and Lactate. Anal Chem 2016; 88:6265-73. [DOI: 10.1021/acs.analchem.6b00272] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cheng-Kuan Su
- Department
of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Shuo-Chih Yen
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, 30013, Taiwan
| | - Tzu-Wen Li
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, 30013, Taiwan
| | - Yuh-Chang Sun
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, 30013, Taiwan
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4
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Petit JM, Magistretti P. Regulation of neuron–astrocyte metabolic coupling across the sleep–wake cycle. Neuroscience 2016; 323:135-56. [DOI: 10.1016/j.neuroscience.2015.12.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/01/2015] [Accepted: 12/04/2015] [Indexed: 11/30/2022]
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5
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Using copper ions to amplify ROS-mediated fluorescence for continuous online monitoring of extracellular glucose in living rat brain. Biosens Bioelectron 2015; 64:535-41. [DOI: 10.1016/j.bios.2014.09.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/28/2014] [Accepted: 09/30/2014] [Indexed: 11/17/2022]
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Inhibition of brain swelling after ischemia-reperfusion by β-adrenergic antagonists: correlation with increased K+ and decreased Ca2+ concentrations in extracellular fluid. BIOMED RESEARCH INTERNATIONAL 2014; 2014:873590. [PMID: 25478577 PMCID: PMC4247955 DOI: 10.1155/2014/873590] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 09/03/2014] [Accepted: 09/10/2014] [Indexed: 12/11/2022]
Abstract
Infarct size and brain edema following ischemia/reperfusion are reduced by inhibitors of the Na+, K+, 2Cl−, and water cotransporter NKCC1 and by β1-adrenoceptor antagonists. NKCC1 is a secondary active transporter, mainly localized in astrocytes, driven by transmembrane Na+/K+ gradients generated by the Na+,K+-ATPase. The astrocytic Na+,K+-ATPase is stimulated by small increases in extracellular K+ concentration and by the β-adrenergic agonist isoproterenol. Larger K+ increases, as occurring during ischemia, also stimulate NKCC1, creating cell swelling. This study showed no edema after 3 hr medial cerebral artery occlusion but pronounced edema after 8 hr reperfusion. The edema was abolished by inhibitors of specifically β1-adrenergic pathways, indicating failure of K+-mediated, but not β1-adrenoceptor-mediated, stimulation of Na+,K+-ATPase/NKCC1 transport during reoxygenation. Ninety percent reduction of extracellular Ca2+ concentration occurs in ischemia. Ca2+ omission abolished K+ uptake in normoxic cultures of astrocytes after addition of 5 mM KCl. A large decrease in ouabain potency on K+ uptake in cultured astrocytes was also demonstrated in Ca2+-depleted media, and endogenous ouabains are needed for astrocytic K+ uptake. Thus, among the ionic changes induced by ischemia, the decrease in extracellular Ca2+ causes failure of the high-K+-stimulated Na+,K+-ATPase/NKCC1 ion/water uptake, making β1-adrenergic activation the only stimulus and its inhibition effective against edema.
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Hertz L, Xu J, Chen Y, Gibbs ME, Du T, Hertz L, Xu J, Chen Y, Gibbs ME, Du T. Antagonists of the Vasopressin V1 Receptor and of the β(1)-Adrenoceptor Inhibit Cytotoxic Brain Edema in Stroke by Effects on Astrocytes - but the Mechanisms Differ. Curr Neuropharmacol 2014; 12:308-23. [PMID: 25342939 PMCID: PMC4207071 DOI: 10.2174/1570159x12666140828222723] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 06/13/2014] [Accepted: 06/20/2014] [Indexed: 01/16/2023] Open
Abstract
Brain edema is a serious complication in ischemic stroke because even relatively small changes in brain volume can compromise cerebral blood flow or result in compression of vital brain structures on account of the fixed volume of the rigid skull. Literature data indicate that administration of either antagonists of the V1 vasopressin (AVP) receptor or the β1-adrenergic receptor are able to reduce edema or infarct size when administered after the onset of ischemia, a key advantage for possible clinical use. The present review discusses possible mechanisms, focusing on the role of NKCC1, an astrocytic cotransporter of Na(+), K(+), 2Cl(-) and water and its activation by highly increased extracellular K(+) concentrations in the development of cytotoxic cell swelling. However, it also mentions that due to a 3/2 ratio between Na(+) release and K(+) uptake by the Na(+),K(+)-ATPase driving NKCC1 brain extracellular fluid can become hypertonic, which may facilitate water entry across the blood-brain barrier, essential for development of edema. It shows that brain edema does not develop until during reperfusion, which can be explained by lack of metabolic energy during ischemia. V1 antagonists are likely to protect against cytotoxic edema formation by inhibiting AVP enhancement of NKCC1-mediated uptake of ions and water, whereas β1-adrenergic antagonists prevent edema formation because β1-adrenergic stimulation alone is responsible for stimulation of the Na(+),K(+)-ATPase driving NKCC1, first and foremost due to decrease in extracellular Ca(2+) concentration. Inhibition of NKCC1 also has adverse effects, e.g. on memory and the treatment should probably be of shortest possible duration.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Junnan Xu
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Ye Chen
- Henry M. Jackson Foundation 6720A Rockledge Dr #100, Bethesda MD 20817, USA
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville, VIC, Australia
| | - Ting Du
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Junnan Xu
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Ye Chen
- Henry M. Jackson Foundation 6720A Rockledge Dr #100, Bethesda MD 20817, USA
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville, VIC, Australia
| | - Ting Du
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
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Rocchitta G, Secchi O, Alvau MD, Farina D, Bazzu G, Calia G, Migheli R, Desole MS, O'Neill RD, Serra PA. Simultaneous telemetric monitoring of brain glucose and lactate and motion in freely moving rats. Anal Chem 2013; 85:10282-8. [PMID: 24102201 DOI: 10.1021/ac402071w] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new telemetry system for simultaneous detection of extracellular brain glucose and lactate and motion is presented. The device consists of dual-channel, single-supply miniature potentiostat-I/V converter, a microcontroller unit, a signal transmitter, and a miniaturized microvibration sensor. Although based on simple and inexpensive components, the biotelemetry device has been used for accurate transduction of the anodic oxidation currents generated on the surface of implanted glucose and lactate biosensors and animal microvibrations. The device was characterized and validated in vitro before in vivo experiments. The biosensors were implanted in the striatum of freely moving animals and the biotelemetric device was fixed to the animal's head. Physiological and pharmacological stimulations were given in order to induce striatal neural activation and to modify the motor behavior in awake, untethered animals.
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Affiliation(s)
- Gaia Rocchitta
- Department of Clinical and Experimental Medicine, Medical School, University of Sassari , Viale S. Pietro 43/b, 07100 Sassari, Italy
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Effects of the neurotoxin MPTP and pargyline protection on extracellular energy metabolites and dopamine levels in the striatum of freely moving rats. Brain Res 2013; 1538:159-71. [PMID: 24080403 DOI: 10.1016/j.brainres.2013.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 08/27/2013] [Accepted: 09/24/2013] [Indexed: 12/25/2022]
Abstract
The neurotoxin MPTP is known to induce dopamine release and depletion of ATP in the striatum of rats. Therefore, we studied the changes induced by MPTP and pargyline protection both on striatal dopamine release and on extracellular energy metabolites in freely moving rats, using dual asymmetric-flow microdialysis. A dual microdialysis probe was inserted in the right striatum of rats. MPTP (25mg/kg, 15mg/kg, 10mg/kg) was intraperitoneally administered for three consecutive days. MAO-B inhibitor pargyline (15mg/kg) was systemically administered before neurotoxin administration. The first MPTP dose induced an increase in dialysate dopamine and a decrease of DOPAC levels in striatal dialysate. After the first neurotoxin administration, increases in striatal glucose, lactate, pyruvate, lactate/pyruvate (L/P) and lactate/glucose (L/G) ratios were observed. Subsequent MPTP administrations showed a progressive reduction of dopamine, glucose and pyruvate levels with a concomitant further increase in lactate levels and L/P and L/G ratios. At day 1, pargyline pre-treatment attenuated the MPTP-induced changes in all studied analytes. Starting from day 2, pargyline prevented the depletion of dopamine, glucose and pyruvate while reduced the increase of lactate, L/P ratio and L/G ratio. These in vivo results suggest a pargyline neuroprotection role against the MPTP-induced energetic impairment consequent to mitochondrial damage. This neuroprotective effect was confirmed by TH immunostaining of the substantia nigra.
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Bazzu G, Biosa A, Farina D, Spissu Y, Dedola S, Calia G, Puggioni G, Rocchitta G, Migheli R, Desole MS, Serra PA. Dual asymmetric-flow microdialysis for in vivo monitoring of brain neurochemicals. Talanta 2011; 85:1933-40. [PMID: 21872041 DOI: 10.1016/j.talanta.2011.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 06/21/2011] [Accepted: 07/07/2011] [Indexed: 01/25/2023]
Abstract
Microdialysis is an extensively used technique for both in vivo and in vitro experiments, applicable to animal and human studies. In neurosciences, the in vivo microdialysis is usually performed to follow changes in the extracellular levels of substances and to monitor neurotransmitters release in the brain of freely moving animals. Catecholamines, such as dopamine and their related compounds, are involved in the neurochemistry and in the physiology of mental diseases and neurological disorders. It is generally supposed that the brain's energy requirement is supplied by glucose oxidation. More recently, lactate was proposed to be the metabolic substrate used by neurons during synaptic activity. In our study, an innovative microdialysis approach for simultaneous monitoring of catecholamines, indolamines, glutamate and energy substrates in the striatum of freely moving rats, using an asymmetric perfusion flow rate on microdialysis probe, is described. As a result of this asymmetric perfusion, two samples are available from the same brain region, having the same analytes composition but different concentrations. The asymmetric flow perfusion could be a useful tool in neurosciences studies related to brain's energy requirement, such as toxin-induced models of Parkinson's disease.
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Affiliation(s)
- Gianfranco Bazzu
- Department of Neuroscience, Medical School, University of Sassari, Viale San Pietro 43/b, 07100 Sassari, Italy.
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Darbin O, Risso J, Carre E, Lonjon M, Naritoku D. Striatal energetic homeostasis under anaesthetic conditions. Brain Res 2011; 1388:157-66. [DOI: 10.1016/j.brainres.2011.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/03/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
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12
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Wang M, Roman GT, Schultz K, Jennings C, Kennedy RT. Improved temporal resolution for in vivo microdialysis by using segmented flow. Anal Chem 2008; 80:5607-15. [PMID: 18547059 PMCID: PMC2597782 DOI: 10.1021/ac800622s] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Microdialysis sampling probes were interfaced to a segmented flow system to improve temporal resolution for monitoring concentration dynamics. Aqueous dialysate was segmented into nanoliter plugs by pumping sample stream into the base of a tee channel structure microfabricated on a PDMS chip that had an immiscible carrier phase (perfluorodecalin) pumped into the cross arm of the tee. Varying the oil flow rate from 0.22 to 6.3 microL/min and sample flow rate from 42 to 328 nL/min allowed control of plug volume, interval between plugs, and frequency of plug generation between 6 and 28 nL, 0.6 and 10 s, and 0.1 and 1.7 Hz, respectively. Temporal resolution of the system, determined by measuring fluorescence in individual sample plugs following step changes of fluorescein concentration at the sampling probe surface, was as good as 15 s. Temporal resolution was independent of both sampling flow rate and distance that samples were pumped from the sampling probe. This effect is due to the prevention of Taylor dispersion of the sample as it was transported by segmented flow. In contrast, without flow segmentation, temporal resolution was worsened from 25 to 160 s as the detection point was moved from the sampling probe to 40 cm downstream. Glucose was detected by modifying the chip to allow enzyme assay reagents to be mixed with dialysate as sample plugs formed. The resulting assay had a detection limit of 50 microM and a linear range of 0.2-2 mM. This system was used to measure glucose in the brain of anesthetized rats. Basal concentration was 1.5 +/- 0.1 mM (n = 3) and was decreased 60% by infusion of high-K(+) solution through the probe. These results demonstrate the potential of microdialysis with segmented flow to be used for in vivo monitoring experiments with high temporal resolution.
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Affiliation(s)
- Meng Wang
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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Ramírez BG, Rodrigues TB, Violante IR, Cruz F, Fonseca LL, Ballesteros P, Castro MMCA, García-Martín ML, Cerdán S. Kinetic properties of the redox switch/redox coupling mechanism as determined in primary cultures of cortical neurons and astrocytes from rat brain. J Neurosci Res 2008; 85:3244-53. [PMID: 17600826 DOI: 10.1002/jnr.21386] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We investigate the mechanisms underlying the redox switch/redox coupling hypothesis by characterizing the competitive consumption of glucose or lactate and the kinetics of pyruvate production in primary cultures of cortical neurons and astrocytes from rat brain. Glucose consumption was determined in neuronal cultures incubated in Krebs ringer bicarbonate buffer (KRB) containing 0.25-5 mM glucose, in the presence and absence of 5 mM lactate as an alternative substrate. Lactate consumption was measured in neuronal cultures incubated with 1-15 mM lactate, in the presence and absence of 1 mM glucose. In both cases, the alternative substrate increased the K(m) (mM) values for glucose consumption (from 2.2 +/- 0.2 to 3.6 +/- 0.1) or lactate consumption (from 7.8 +/- 0.1 to 8.5 +/- 0.1) without significant changes on the corresponding V(max). This is consistent with a competitive inhibition between the simultaneous consumption of glucose and lactate. When cultures of neurons or astrocytes were incubated with increasing lactate concentrations 1-20 mM, pyruvate production was observed with K(m) (mM) and V(max) (nmol/mg/h) values of 1.0 +/- 0.1 and 109 +/- 4 in neurons, or 0.28 +/- 0.1 and 342 +/- 54 in astrocytes. Thus, astrocytes or neurons are able to return to the incubation medium as pyruvate, a significant part of the lactate consumed. Present results support the reversible exchange of reducing equivalents between neurons and astrocytes in the form of lactate or pyruvate. Monocarboxylate exchange is envisioned to operate under near equilibrium, with the transcellular flux directed thermodynamically toward the more oxidized intracellular redox environment.
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Affiliation(s)
- Belén G Ramírez
- Laboratory for Imaging and Spectroscopy by Magnetic Resonance LISMAR, Instituto de Investigaciones Biomédicas Alberto Sols CSIC/UAM, Madrid, Spain
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