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Ebersole J, Rose G, Eid T, Behar K, Patrylo P. Altered hippocampal astroglial metabolism is associated with aging and preserved spatial learning and memory. Neurobiol Aging 2021; 102:188-199. [PMID: 33774381 DOI: 10.1016/j.neurobiolaging.2021.02.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022]
Abstract
An age-related decrease in hippocampal metabolism correlates with cognitive decline. Hippocampus-dependent learning and memory requires glutamatergic neurotransmission supported by glutamate-glutamine (GLU-GLN) cycling between neurons and astrocytes. We examined whether GLU-GLN cycling in hippocampal subregions (dentate gyrus and CA1) in Fischer 344 rats was altered with age and cognitive status. Hippocampal slices from young adult, aged cognitively-unimpaired (AU) and aged cognitively-impaired (AI) rats were incubated in artificial cerebrospinal fluid (aCSF) containing 1-13C-glucose to assess neural metabolism. Incorporation of 13C-glucose into glutamate and glutamine, measured by mass spectroscopy/liquid chromatography tandem mass spectroscopy, did not significantly differ between groups. However, when 13C-acetate, a preferential astrocytic metabolite, was used, a significant increase in 13C-labeled glutamate was observed in slices from AU rats. Taken together, the data suggest that resting state neural metabolism and GLU-GLN cycling may be preserved during aging when sufficient extracellular glucose is available, but that enhanced astroglial metabolism can occur under resting state conditions. This may be an aging-related compensatory change to maintain hippocampus-dependent cognitive function.
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Affiliation(s)
- Jeremy Ebersole
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Gregory Rose
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Tore Eid
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; MRRC Neurometabolism Research Laboratory, Yale University School of Medicine, New Haven, CT, USA
| | - Peter Patrylo
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA.
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Boillat Y, Xin L, van der Zwaag W, Gruetter R. Metabolite concentration changes associated with positive and negative BOLD responses in the human visual cortex: A functional MRS study at 7 Tesla. J Cereb Blood Flow Metab 2020; 40:488-500. [PMID: 30755134 PMCID: PMC7026843 DOI: 10.1177/0271678x19831022] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Negative blood oxygenation-level dependent (BOLD) signal observed during task execution in functional magnetic resonance imaging (fMRI) can be caused by different mechanisms, such as a blood-stealing effect or neuronal deactivation. Electrophysiological recordings showed that neuronal deactivation underlies the negative BOLD observed in the occipital lobe during visual stimulation. In this study, the metabolic demand of such a response was studied by measuring local metabolite concentration changes during a visual checkerboard stimulation using functional magnetic resonance spectroscopy (fMRS) at 7 Tesla. The results showed increases of glutamate and lactate concentrations during the positive BOLD response, consistent with previous fMRS studies. In contrast, during the negative BOLD response, decreasing concentrations of glutamate, lactate and gamma-aminobutyric acid (GABA) were found, suggesting a reduction of glycolytic and oxidative metabolic demand below the baseline. Additionally, the respective changes of the BOLD signal, glutamate and lactate concentrations of both groups suggest that a local increase of inhibitory activity might occur during the negative BOLD response.
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Affiliation(s)
- Yohan Boillat
- Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- Animal imaging and technology core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Wietske van der Zwaag
- Animal imaging and technology core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Spinoza Centre for Neuroimaging, Amsterdam, Netherlands
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Animal imaging and technology core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Geneva, Geneva, Switzerland.,Department of Radiology, University of Lausanne, Lausanne, Switzerland
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Wu P, Bjørn-Yoshimoto WE, Staudt M, Jensen AA, Bunch L. Identification and Structure-Activity Relationship Study of Imidazo[1,2- a]pyridine-3-amines as First Selective Inhibitors of Excitatory Amino Acid Transporter Subtype 3 (EAAT3). ACS Chem Neurosci 2019; 10:4414-4429. [PMID: 31573179 DOI: 10.1021/acschemneuro.9b00447] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In the present study, screening of a library of 49,087 compounds at the excitatory amino acid transporter subtype 3 (EAAT3) led to the identification of 2-(furan-2-yl)-8-methyl-N-(o-tolyl)imidazo[1,2-a]pyridin-3-amine (3a) which showed a >20-fold preference for inhibition of EAAT3 (IC50 = 13 μM) over EAAT1,2,4 (EAAT1: IC50 ∼ 250 μM; EAAT2,4: IC50 > 250 μM). It was shown that a small lipophilic substituent (methyl or bromine) at the 7- and/or 8-position was essential for activity. Furthermore, the substitution pattern of the o-tolyl group (compound 5b) and the chemical nature of the substituent in the 2-position (compound 7b) were shown to be essential for the selectivity toward EAAT3 over EAAT1,2. The most prominent analogues to come out of this study are 3a and 3e that display ∼35-fold selectivity for EAAT3 (IC50 = 7.2 μM) over EAAT1,2,4 (IC50 ∼ 250 μM).
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Affiliation(s)
- Peng Wu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Walden E. Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Markus Staudt
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
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Is plasma GABA level a biomarker of Post-Traumatic Stress Disorder (PTSD) severity? A preliminary study. Psychiatry Res 2016; 241:273-9. [PMID: 27208514 DOI: 10.1016/j.psychres.2016.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 11/22/2022]
Abstract
OBJECTIVES An increased reactivity to the environment is observed in Post-Traumatic Stress Disorder (PTSD). It would be related to impairment of the Gamma Amino Butyric Acid (GABA) neurotransmission. The study aimed to evaluate plasma GABA concentration as a candidate for PTSD severity biomarker. METHODS This hypothesis was studied in 17 PTSD patients and 17 healthy Controls using classic and emotional Stroop paradigms. Plasma GABA concentrations were assessed before and after both Stroop tests to evaluate GABA basal tone and GABA reactivity (change in GABAp), respectively. RESULTS During baseline, PTSD had lower plasma GABA concentrations than the Controls. After the Stroop conflicts GABA reactivity was also lower in PTSD than in the Controls. The GABA baseline tone was negatively correlated with the severity of the PTSD symptoms. This relation was only marginally observed for GABA reactivity. The results produced a trend due to the small size of the sample compared to the number of statistical results given. CONCLUSION Altogether, the reduced GABA concentration observed in PTSD could be considered as a possible biomarker for PTSD severity.
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Bjørn-Yoshimoto WE, Underhill SM. The importance of the excitatory amino acid transporter 3 (EAAT3). Neurochem Int 2016; 98:4-18. [PMID: 27233497 DOI: 10.1016/j.neuint.2016.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/09/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022]
Abstract
The neuronal excitatory amino acid transporter 3 (EAAT3) is fairly ubiquitously expressed in the brain, though it does not necessarily maintain the same function everywhere. It is important in maintaining low local concentrations of glutamate, where its predominant post-synaptic localization can buffer nearby glutamate receptors and modulate excitatory neurotransmission and synaptic plasticity. It is also the main neuronal cysteine uptake system acting as the rate-limiting factor for the synthesis of glutathione, a potent antioxidant, in EAAT3 expressing neurons, while on GABAergic neurons, it is important in supplying glutamate as a precursor for GABA synthesis. Several diseases implicate EAAT3, and modulation of this transporter could prove a useful therapeutic approach. Regulation of EAAT3 could be targeted at several points for functional modulation, including the level of transcription, trafficking and direct pharmacological modulation, and indeed, compounds and experimental treatments have been identified that regulate EAAT3 function at different stages, which together with observations of EAAT3 regulation in patients is giving us insight into the endogenous function of this transporter, as well as the consequences of altered function. This review summarizes work done on elucidating the role and regulation of EAAT3.
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Affiliation(s)
- Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Suzanne M Underhill
- National Institute of Mental Health, National Institutes of Health, 35 Convent Drive Room 3A: 210 MSC3742, Bethesda, MD 20892-3742, USA.
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Microperfusion of 3-MPA into the brain augments GABA. Epilepsy Behav 2013; 29:478-84. [PMID: 24094842 PMCID: PMC3939839 DOI: 10.1016/j.yebeh.2013.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/25/2013] [Accepted: 08/26/2013] [Indexed: 11/23/2022]
Abstract
In vivo effects of microperfusion of a GABA synthesis inhibitor (3-MPA) into the striatum and hippocampus on amino acid concentrations and electrical neuronal activity were investigated. Paradoxical elevations in GABA in the striatum (5-fold in anesthetized and 50-fold in awake rats) and hippocampus (2-fold in anesthetized and 15-fold in awake rats) were documented under steady-state concentrations of 3-MPA along with expected increases in glutamate (a 15-fold increase and a 250-fold increase in the striatum of anesthetized and awake rats, respectively; a 7-fold increase and a 25-fold increase in the hippocampus of anesthetized and awake rats, respectively). There was no clear epileptiform or seizure activity. Explanations for the paradoxical increase in GABA are offered, and emphasis is placed on the dependency of disinhibition on the model in which its effects are studied as well as on the prevailing level of activation of the probed network.
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Rae CD. A Guide to the Metabolic Pathways and Function of Metabolites Observed in Human Brain 1H Magnetic Resonance Spectra. Neurochem Res 2013; 39:1-36. [PMID: 24258018 DOI: 10.1007/s11064-013-1199-5] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 12/20/2022]
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Rapid, activity-independent turnover of vesicular transmitter content at a mixed glycine/GABA synapse. J Neurosci 2013; 33:4768-81. [PMID: 23486948 DOI: 10.1523/jneurosci.5555-12.2013] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The release of neurotransmitter via the fusion of transmitter-filled, presynaptic vesicles is the primary means by which neurons relay information. However, little is known regarding the molecular mechanisms that supply neurotransmitter destined for vesicle filling, the endogenous transmitter concentrations inside presynaptic nerve terminals, or the dynamics of vesicle refilling after exocytosis. We addressed these issues by recording from synaptically coupled pairs of glycine/GABA coreleasing interneurons (cartwheel cells) of the mouse dorsal cochlear nucleus. We find that the plasma membrane transporter GlyT2 and the intracellular enzyme glutamate decarboxylase supply the majority of glycine and GABA, respectively. Pharmacological block of GlyT2 or glutamate decarboxylase led to rapid and complete rundown of transmission, whereas increasing GABA synthesis via intracellular glutamate uncaging dramatically potentiated GABA release within 1 min. These effects were surprisingly independent of exocytosis, indicating that prefilled vesicles re-equilibrated upon acute changes in cytosolic transmitter. Titration of cytosolic transmitter with postsynaptic responses indicated that endogenous, nonvesicular glycine/GABA levels in nerve terminals are 5-7 mm, and that vesicular transport mechanisms are not saturated under basal conditions. Thus, cytosolic transmitter levels dynamically set the strength of inhibitory synapses in a release-independent manner.
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Maddock RJ, Buonocore MH. MR spectroscopic studies of the brain in psychiatric disorders. Curr Top Behav Neurosci 2012; 11:199-251. [PMID: 22294088 DOI: 10.1007/7854_2011_197] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The measurement of brain metabolites with magnetic resonance spectroscopy (MRS) provides a unique perspective on the brain bases of neuropsychiatric disorders. As a context for interpreting MRS studies of neuropsychiatric disorders, we review the characteristic MRS signals, the metabolic dynamics,and the neurobiological significance of the major brain metabolites that can be measured using clinical MRS systems. These metabolites include N-acetylaspartate(NAA), creatine, choline-containing compounds, myo-inositol, glutamate and glutamine, lactate, and gamma-amino butyric acid (GABA). For the major adult neuropsychiatric disorders (schizophrenia, bipolar disorder, major depression, and the anxiety disorders), we highlight the most consistent MRS findings, with an emphasis on those with potential clinical or translational significance. Reduced NAA in specific brain regions in schizophrenia, bipolar disorder, post-traumatic stress disorder, and obsessive–compulsive disorder corroborate findings of reduced brain volumes in the same regions. Future MRS studies may help determine the extent to which the neuronal dysfunction suggested by these findings is reversible in these disorders. Elevated glutamate and glutamine (Glx) in patients with bipolar disorder and reduced Glx in patients with unipolar major depression support models of increased and decreased glutamatergic function, respectively, in those conditions. Reduced phosphomonoesters and intracellular pH in bipolar disorder and elevated dynamic lactate responses in panic disorder are consistent with metabolic models of pathogenesis in those disorders. Preliminary findings of an increased glutamine/glutamate ratio and decreased GABA in patients with schizophrenia are consistent with a model of NMDA hypofunction in that disorder. As MRS methods continue to improve, future studies may further advance our understanding of the natural history of psychiatric illnesses, improve our ability to test translational models of pathogenesis, clarify therapeutic mechanisms of action,and allow clinical monitoring of the effects of interventions on brain metabolicmarkers
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Nasrallah FA, Balcar VJ, Rae CD. Activity-dependent γ-aminobutyric acid release controls brain cortical tissue slice metabolism. J Neurosci Res 2011; 89:1935-45. [DOI: 10.1002/jnr.22649] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/15/2011] [Accepted: 03/01/2011] [Indexed: 12/16/2022]
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Role of Glutamate and GABA in Mechanisms Underlying Respiratory Control. NEUROPHYSIOLOGY+ 2011. [DOI: 10.1007/s11062-011-9162-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bryant AS, Li B, Beenhakker MP, Huguenard JR. Maintenance of thalamic epileptiform activity depends on the astrocytic glutamate-glutamine cycle. J Neurophysiol 2009; 102:2880-8. [PMID: 19741104 DOI: 10.1152/jn.00476.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The generation of prolonged neuronal activity depends on the maintenance of synaptic neurotransmitter pools. The astrocytic glutamate-glutamine cycle is a major mechanism for recycling the neurotransmitters GABA and glutamate. Here we tested the effect of disrupting the glutamate-glutamine cycle on two types of neuronal activity patterns in the thalamus: sleep-related spindles and epileptiform oscillations. In recording conditions believed to induce glutamine scarcity, epileptiform oscillations showed a progressive reduction in duration that was partially reversible by the application of exogenous glutamine (300 muM). Blocking uptake of glutamine into neurons with alpha-(methylamino) isobutyric acid (5 mM) caused a similar reduction in oscillation duration, as did blocking neuronal GABA synthesis with 3-mercaptoproprionic acid (10 muM). However, comparable manipulations did not affect sleep spindles. Together, these results support a crucial role for the glutamate-glutamine cycle in providing the neurotransmitters necessary for the generation of epileptiform activity and suggest potential therapeutic approaches that selectively reduce seizure activity but maintain normal neuronal activity.
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Affiliation(s)
- Astra S Bryant
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305-5122, USA
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Page KA, Williamson A, Yu N, McNay EC, Dzuira J, McCrimmon RJ, Sherwin RS. Medium-chain fatty acids improve cognitive function in intensively treated type 1 diabetic patients and support in vitro synaptic transmission during acute hypoglycemia. Diabetes 2009; 58:1237-44. [PMID: 19223595 PMCID: PMC2671041 DOI: 10.2337/db08-1557] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE We examined whether ingestion of medium-chain triglycerides could improve cognition during hypoglycemia in subjects with intensively treated type 1 diabetes and assessed potential underlying mechanisms by testing the effect of beta-hydroxybutyrate and octanoate on rat hippocampal synaptic transmission during exposure to low glucose. RESEARCH DESIGN AND METHODS A total of 11 intensively treated type 1 diabetic subjects participated in stepped hyperinsulinemic- (2 mU x kg(-1) x min(-1)) euglycemic- (glucose approximately 5.5 mmol/l) hypoglycemic (glucose approximately 2.8 mmol/l) clamp studies. During two separate sessions, they randomly received either medium-chain triglycerides or placebo drinks and performed a battery of cognitive tests. In vitro rat hippocampal slice preparations were used to assess the ability of beta-hydroxybutyrate and octanoate to support neuronal activity when glucose levels are reduced. RESULTS Hypoglycemia impaired cognitive performance in tests of verbal memory, digit symbol coding, digit span backwards, and map searching. Ingestion of medium-chain triglycerides reversed these effects. Medium-chain triglycerides also produced higher free fatty acids and beta-hydroxybutyrate levels compared with placebo. However, the increase in catecholamines and symptoms during hypoglycemia was not altered. In hippocampal slices beta-hydroxybutyrate supported synaptic transmission under low-glucose conditions, whereas octanoate could not. Nevertheless, octanoate improved the rate of recovery of synaptic function upon restoration of control glucose concentrations. CONCLUSIONS Medium-chain triglyceride ingestion improves cognition without adversely affecting adrenergic or symptomatic responses to hypoglycemia in intensively treated type 1 diabetic subjects. Medium-chain triglycerides offer the therapeutic advantage of preserving brain function under hypoglycemic conditions without causing deleterious hyperglycemia.
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Affiliation(s)
- Kathleen A Page
- Section of Endocrinology, Yale School of Medicine, New Haven, Connecticut, USA.
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Kumar M, Tyagi N, Moshal KS, Sen U, Kundu S, Mishra PK, Givvimani S, Tyagi SC. Homocysteine decreases blood flow to the brain due to vascular resistance in carotid artery. Neurochem Int 2008; 53:214-9. [PMID: 18725259 DOI: 10.1016/j.neuint.2008.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 07/24/2008] [Accepted: 07/25/2008] [Indexed: 02/02/2023]
Abstract
An elevated level of Homocysteine (Hcy) is a risk factor for vascular dementia and stroke. Cysthathionine beta Synthase (CBS) gene is involved in the clearance of Hcy. Homozygous individuals for (CBS-/-) die early, but heterozygous for (CBS-/+) survive with high levels of Hcy. The gamma-Amino Butyric Acid (GABA) presents in the central nervous system (CNS) and functions as an inhibitory neurotransmitter. Hcy competes with GABA at the GABA(A) receptor and affects the CNS function. We hypothesize that Hcy causes a decrease in blood flow to the brain due to increase in vascular resistance (VR) because of arterial remodeling in the carotid artery (CA). Blood pressure and blood flow in CA of wild type (WT), CBS-/+, CBS-/+ GABA(A)-/- double knockout, and GABA(A)-/- were measured. CA was stained with trichrome, and the brain permeability was measured. Matrix Metalloproteinases (MMP-2 and MMP-9), tissue inhibitor of metalloproteinase (TIMP-3, TIMP-4), elastin, and collagen-III expression were measured by real-time polymerase chain reaction (RT-PCR). Results showed an increase in VR in CBS-/+/GABA(A)-/-double knockout>CBS-/+/>GABA(A)-/- compared to WT mice. Increased MMP-2, MMP-9, collagen-III and TIMP-3 mRNA levels were found in GABA(A)-/-, CBS-/+, CBS-/+/GABA(A) double knockout compared to WT. The levels of TIMP-4 and elastin were decreased, whereas the levels of MMP-2, MMP-9 and TIMP-3 increased, which indirectly reflected the arterial resistance. These results suggested that Hcy caused arterial remodeling in part, by increase in collagen/elastin ratio thereby increasing VR leading to the decrease in CA blood flow.
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Affiliation(s)
- Munish Kumar
- Department of Physiology & Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA
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