scholarly journals Ginkgo Extract EGb761 Confers Neuroprotection by Reduction of Glutamate Release in Ischemic Brain

2012 ◽  
Vol 15 (1) ◽  
pp. 94 ◽  
Author(s):  
Alexander Mdzinarishvili ◽  
Rachita K. Sambria ◽  
Dorothee Lang ◽  
Jochen Klein
Keyword(s):  
Glutamate Release ◽  
Hippocampal Slices ◽  
Brain Slices ◽  
Cell Swelling ◽  
Experimental Stroke ◽  
Cell Degeneration ◽  
Edema Formation ◽  
Ginkgo Extract

Purpose - Ginkgo extract EGb761 has shown anti-edema and anti-ischemic effects in various experimental models. In the present study, we demonstrate neuroprotective effects of EGb761 in experimental stroke while monitoring brain metabolism by microdialysis. Methods - We have used oxygen-glucose deprivation in brain slices in vitro and middle cerebral artery occlusion (MCAO) in vivo to induce ischemia in mouse brain. We used microdialysis in mouse striatum to monitor extracellular concentrations of glucose and glutamate. Results - In vitro, EGb761 reduced ischemia-induced cell swelling in hippocampal slices by 60%. In vivo, administration of EGb761 (300 mg/kg) reduced cell degeneration and edema formation after MCAO by 35-50%. Immediately following MCAO, striatal glucose levels dropped to 25% of controls, and this reduction was not significantly affected by EGb761. Striatal glutamate levels, in contrast, increased 15-fold after MCAO; after pretreatment with EGb761, glutamate levels only increased by 4-5fold. Conclusions - We show that pretreatment with EGb761 strongly reduces cellular edema formation and neurodegeneration under conditions of ischemia. The mechanism of action seems to be related to a reduction of excitotoxicity, because ischemia-induced release of glutamate was strongly suppressed. Ginkgo extracts such as EGb761 may be valuable to prevent ischemia-induced damage in stroke-prone patients. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

scholarly journals Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport

2015 ◽  
Vol 309 (4) ◽  
pp. E370-E379 ◽  
Author(s):  
Keeley L. Rose ◽  
Andrew J. Watson ◽  
Thomas A. Drysdale ◽  
Gediminas Cepinskas ◽  
Melissa Chan ◽  
...  
Keyword(s):  
Diabetic Ketoacidosis ◽  
Hydrogen Exchange ◽  
Brain Slices ◽  
Anion Transport ◽  
Brain Cell ◽  
Cell Swelling ◽  
Sodium Hydrogen ◽  
Disulphonic Acid

A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.

Hypothermia and Isoflurane Similarly Inhibit Glutamate Release Evoked by Chemical Anoxia in Rat Cortical Brain Slices

1996 ◽  
Vol 85 (3) ◽  
pp. 600-607. ◽  
Author(s):  
Helge Eilers ◽  
Philip E. Bickler
Keyword(s):  
Minimum Alveolar Concentration ◽  
Glutamate Release ◽  
Brain Slices ◽  
Neuronal Cell ◽  
Release Rates ◽  
Neuroprotective Effects ◽  
In Vivo Models ◽  
Chemical Anoxia

Background Accumulation of the excitatory neurotransmitter glutamate in ischemic brain tissue contributes to neuronal cell death. Volatile anesthetics at clinically relevant concentrations are neuroprotective in in vivo models of brain ischemia and reduce glutamate release in vivo and in vitro, but they appear to have weaker neuroprotective effects than hypothermia. The purpose of this study was to determine whether isoflurane reduces glutamate release in hypoxic brain slices, how large this effect is compared to that of hypothermia, and if it is diminished by hyperthermia. Methods Glutamate released from rat cortical brain slices during chemical anoxia (100 microM NaCN) was measured continuously with a fluorescence assay. The release rate was compared at three temperatures (28 degrees C, 37 degrees C, and 39 degrees C) with and without isoflurane at concentrations equipotent to 1 minimum alveolar concentration. At the same three temperatures, glutamate release rates before and after exposure to isoflurane were compared. Results Isoflurane reduced glutamate release from brain slices during chemical anoxia at 37 degrees C (19.6%, P < 0.01) and at 39 degrees C (25.4%, P < 0.01), but not at 28 degrees C. The reduction in glutamate release with hypothermia was similar to that with isoflurane. Hyperthermia (39 degrees C) caused greater glutamate release under basal and anoxic conditions than normo- and hypothermia. Isoflurane caused a slight increase in basal glutamate release rates, although this effect was smaller than the increase caused by hyperthermia. Conclusions In a brain slice model of cerebral anoxia, 1 minimum alveolar concentration isoflurane decreases glutamate release to a similar extent that hypothermia (28 degrees C) does. The increased glutamate release with hyperthermia (39 degrees C) is not prevented by isoflurane.

Ascorbic acid, but not glutathione, is taken up by brain slices and preserves cell morphology

1994 ◽  
Vol 71 (4) ◽  
pp. 1591-1596 ◽  
Author(s):  
M. E. Rice ◽  
M. A. Perez-Pinzon ◽  
E. J. Lee
Keyword(s):  
Ascorbic Acid ◽  
Cell Morphology ◽  
Hippocampal Slices ◽  
Brain Slices ◽  
Neuronal Loss ◽  
Pyramidal Cells ◽  
Cresyl Violet ◽  
Intact Tissue

1. We have determined the ascorbic acid (ascorbate) and glutathione (GSH) content of cortical and hippocampal slices from rat brain after prolonged (6h) incubation and have correlated these levels with the histological quality of the slices. Ascorbate and GSH levels in control and sliced tissue were determined by high performance liquid chromatography (HPLC) with electrochemical detection. Cell morphology of incubated slices was compared with that of intact tissue in cresyl violet stained tissue sections. 2. Roughly 70% of tissue ascorbate and GSH was lost from slices during incubation in vitro. Normal in vivo levels of ascorbate (2-3 mumol g-1 tissue wet weight) could be maintained by including 200-400 microM ascorbate (typical extracellular concentration) in the incubation media. By contrast, the loss of GSH could not be prevented by incubation with GSH. 3. The morphology of cells in hippocampal slices incubated under conditions that maintained ascorbate content and compartmentalization were similar to those of intact tissue. Ascorbate protected pyramidal cells in CA1 and CA3 regions of the hippocampus from the degeneration that was seen in slices incubated in ascorbate-free media. 4. These data suggest that loss of endogenous antioxidants may be a major factor in neuronal loss in vitro and support the notion that ascorbate is an endogenous neuroprotective agent.

scholarly journals Development of 18F-Labeled Radiotracers for PET Imaging of the Adenosine A2A Receptor: Synthesis, Radiolabeling and Preliminary Biological Evaluation

2021 ◽  
Vol 22 (5) ◽  
pp. 2285
Author(s):  
Thu Hang Lai ◽  
Susann Schröder ◽  
Magali Toussaint ◽  
Sladjana Dukić-Stefanović ◽  
Mathias Kranz ◽  
...  
Keyword(s):  
Specific Binding ◽  
Brain Slices ◽  
Total Activity ◽  
Biological Evaluation ◽  
Adenosine A2a Receptor ◽  
Positron Emission ◽  
A2a Receptor ◽  
Adenosine A2a

The adenosine A2A receptor (A2AR) represents a potential therapeutic target for neurodegenerative diseases. Aiming at the development of a positron emission tomography (PET) radiotracer to monitor changes of receptor density and/or occupancy during the A2AR-tailored therapy, we designed a library of fluorinated analogs based on a recently published lead compound (PPY). Among those, the highly affine 4-fluorobenzyl derivate (PPY1; Ki(hA2AR) = 5.3 nM) and the 2-fluorobenzyl derivate (PPY2; Ki(hA2AR) = 2.1 nM) were chosen for 18F-labeling via an alcohol-enhanced copper-mediated procedure starting from the corresponding boronic acid pinacol ester precursors. Investigations of the metabolic stability of [18F]PPY1 and [18F]PPY2 in CD-1 mice by radio-HPLC analysis revealed parent fractions of more than 76% of total activity in the brain. Specific binding of [18F]PPY2 on mice brain slices was demonstrated by in vitro autoradiography. In vivo PET/magnetic resonance imaging (MRI) studies in CD-1 mice revealed a reasonable high initial brain uptake for both radiotracers, followed by a fast clearance.

Physiology, Pharmacology, and Topography of Cholinergic Neocortical Oscillations In Vitro

1997 ◽  
Vol 77 (5) ◽  
pp. 2427-2445 ◽  
Author(s):  
Heath S. Lukatch ◽  
M. Bruce Maciver
Keyword(s):  
Current Source ◽  
Brain Slices ◽  
Receptor Activation ◽  
Brain Regions ◽  
Oscillatory Activity ◽  
Cortical Layers ◽  
Eeg Activity ◽  
Layer 2

Lukatch, Heath S. and M. Bruce MacIver. Physiology, pharmacology, and topography of cholinergic neocortical oscillations in vitro. J. Neurophysiol. 77: 2427–2445, 1997. Rat neocortical brain slices generated rhythmic extracellular field [microelectroencephalogram (micro-EEG)] oscillations at theta frequencies (3–12 Hz) when exposed to pharmacological conditions that mimicked endogenous ascending cholinergic and GABAergic inputs. Use of the specific receptor agonist and antagonist carbachol and bicuculline revealed that simultaneous muscarinic receptor activation and γ-aminobutyric acid-A (GABAA)-mediated disinhibition werenecessary to elicit neocortical oscillations. Rhythmic activity was independent of GABAB receptor activation, but required intact glutamatergic transmission, evidenced by blockade or disruption of oscillations by 6-cyano-7-nitroquinoxaline-2,3-dione and (±)-2-amino-5-phosphonovaleric acid, respectively. Multisite mapping studies showed that oscillations were localized to areas 29d and 18b (Oc2MM) and parts of areas 18a and 17. Peak oscillation amplitudes occurred in layer 2/3, and phase reversals were observed in layers 1 and 5. Current source density analysis revealed large-amplitude current sinks and sources in layers 2/3 and 5, respectively. An initial shift in peak inward current density from layer 1 to layer 2/3 indicated that two processes underlie an initial depolarization followed by oscillatory activity. Laminar transections localized oscillation-generating circuitry to superficial cortical layers and sharp-spike-generating circuitry to deep cortical layers. Whole cell recordings identified three distinct cell types based on response properties during rhythmic micro-EEG activity: oscillation-on (theta-on) and -off (theta-off) neurons, and transiently depolarizing glial cells. Theta-on neurons displayed membrane potential oscillations that increased in amplitude with hyperpolarization (from −30 to −90 mV). This, taken together with a glutamate antagonist-induced depression of rhythmic micro-EEG activity, indicated that cholinergically driven neocortical oscillations require excitatory synaptic transmission. We conclude that under the appropriate pharmacological conditions, neocortical brain slices were capable of producing localized theta frequency oscillations. Experiments examining oscillation physiology, pharmacology, and topography demonstrated that neocortical brain slice oscillations share many similarities with the in vivo and in vitro theta EEG activity recorded in other brain regions.

Opioids and testicular activity in the frog, Rana esculenta

1993 ◽  
Vol 137 (1) ◽  
pp. 49-NP ◽  
Author(s):  
F. Facchinetti ◽  
A. R. Genazzani ◽  
M. Vallarino ◽  
M. Pestarino ◽  
A. Polzonetti-Magni ◽  
...  
Keyword(s):  
Physiological Activity ◽  
Mammalian Species ◽  
Rana Esculenta ◽  
Cell Degeneration ◽  
Efferent System ◽  
Naltrexone Treatment ◽  
Nucleus Infundibularis ◽  
The Brain

ABSTRACT The presence and activity of brain, pituitary and testicular β-endorphin (β-EP)-like material have been studied in the frog, Rana esculenta, using reverse-phase high-pressure liquid chromatography, coupled with radioimmunoassay and immunocytochemistry. In-vivo and in-vitro treatments with naltrexone were carried out to assess the putative physiological activity of opioid peptides. β(1–31) and (1–27), together with their acetylated forms, have been identified in brain, pituitary and testis. In particular, β-EP(1–31) concentrations peaked during July in the brain and pituitary, whilst in testes maximum concentrations were found in April and November. β-EP immunoreactivity was present in the brain within the nucleus preopticus and nucleus infundibularis ventralis while positive fibres in the retrochiasmatic regions projected to the median eminence. In the testis, interstitial cells, canaliculi of the efferent system, spermatogonia and spermatocytes showed positive immunostaining for β-EP. In intact animals, naltrexone treatment increased plasma and testicular androgen levels and this effect was confirmed in in-vitro incubations of minced testes. Naltrexone also induced a significant increase in germ cell degeneration. Our results indicated that an opioid system modulates the hypothalamus-pituitary-gonadal axis in the frog, Rana esculenta and, for the first time, we have shown that the testicular activity of a non-mammalian species may be regulated by opiates locally. Journal of Endocrinology (1993) 137, 49–57

Electrophysiological characterization and computational models of HVC neurons in the zebra finch

2013 ◽  
Vol 110 (5) ◽  
pp. 1227-1245 ◽  
Author(s):  
Arij Daou ◽  
Matthew T. Ross ◽  
Frank Johnson ◽  
Richard L. Hyson ◽  
Richard Bertram
Keyword(s):  
Computational Models ◽  
Premotor Cortex ◽  
Brain Slices ◽  
Ionic Currents ◽  
Proper Name ◽  
Using Data ◽  
Electrophysiological Characterization

The nucleus HVC (proper name) within the avian analog of mammal premotor cortex produces stereotyped instructions through the motor pathway leading to precise, learned vocalization by songbirds. Electrophysiological characterization of component HVC neurons is an important requirement in building a model to understand HVC function. The HVC contains three neural populations: neurons that project to the RA (robust nucleus of arcopallium), neurons that project to Area X (of the avian basal ganglia), and interneurons. These three populations are interconnected with specific patterns of excitatory and inhibitory connectivity, and they fire with characteristic patterns both in vivo and in vitro. We performed whole cell current-clamp recordings on HVC neurons within brain slices to examine their intrinsic firing properties and determine which ionic currents are responsible for their characteristic firing patterns. We also developed conductance-based models for the different neurons and calibrated the models using data from our brain slice work. These models were then used to generate predictions about the makeup of the ionic currents that are responsible for the different responses to stimuli. These predictions were then tested and verified in the slice using pharmacological manipulations. The model and the slice work highlight roles of a hyperpolarization-activated inward current ( Ih), a low-threshold T-type Ca2+ current ( ICa-T), an A-type K+ current ( IA), a Ca2+-activated K+ current ( ISK), and a Na+-dependent K+ current ( IKNa) in driving the characteristic neural patterns observed in the three HVC neuronal populations. The result is an improved characterization of the HVC neurons responsible for song production in the songbird.

TMOD-31. AN ORGANOTYPIC TISSUE PLATFORM TO BRIDGE IN VITRO AND IN VIVO ASSAYS FOR BRAIN CANCER TREATMENT

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi222-vi222
Author(s):  
Breanna Mann ◽  
Noah Bell ◽  
Denise Dunn ◽  
Scott Floyd ◽  
Shawn Hingtgen ◽  
...  
Keyword(s):  
Cell Lines ◽  
Brain Cancer ◽  
Brain Slice ◽  
Brain Slices ◽  
In Vitro Assays ◽  
Preclinical Model ◽  
Short Period ◽  
The Brain

Abstract Brain cancers remain one of the greatest medical challenges. The lack of experimentally tractable models that recapitulate brain structure/function represents a major impediment. Platforms that enable functional testing in high-fidelity models are urgently needed to accelerate the identification and translation of therapies to improve outcomes for patients suffering from brain cancer. In vitro assays are often too simple and artificial while in vivo studies can be time-intensive and complicated. Our live, organotypic brain slice platform can be used to seed and grow brain cancer cell lines, allowing us to bridge the existing gap in models. These tumors can rapidly establish within the brain slice microenvironment, and morphologic features of the tumor can be seen within a short period of time. The growth, migration, and treatment dynamics of tumors seen on the slices recapitulate what is observed in vivo yet is missed by in vitro models. Additionally, the brain slice platform allows for the dual seeding of different cell lines to simulate characteristics of heterogeneous tumors. Furthermore, live brain slices with embedded tumor can be generated from tumor-bearing mice. This method allows us to quantify tumor burden more effectively and allows for treatment and retreatment of the slices to understand treatment response and resistance that may occur in vivo. This brain slice platform lays the groundwork for a new clinically relevant preclinical model which provides physiologically relevant answers in a short amount of time leading to an acceleration of therapeutic translation.

scholarly journals Epileptiform Discharges With In-Vivo-Like Features in Slices of Rat Piriform Cortex With Longitudinal Association Fibers

2001 ◽  
Vol 86 (5) ◽  
pp. 2445-2460 ◽  
Author(s):  
Rezan Demir ◽  
Lewis B. Haberly ◽  
Meyer B. Jackson
Keyword(s):  
Seizure Activity ◽  
Epileptiform Activity ◽  
Piriform Cortex ◽  
Brain Slices ◽  
Epileptiform Discharges ◽  
Local Circuitry ◽  
Association Fibers ◽  
Discharge Propagation

Brain slices serve as useful models for the investigation of epilepsy. However, the preparation of brain slices disrupts circuitry and severs axons, thus complicating efforts to relate epileptiform activity in vitro to seizure activity in vivo. This issue is relevant to studies in transverse slices of the piriform cortex (PC), the preparation of which disrupts extensive rostrocaudal fiber systems. In these slices, epileptiform discharges propagate slowly and in a wavelike manner, whereas such discharges in vivo propagate more rapidly and jump abruptly between layers. The objective of the present study was to identify fiber systems responsible for these differences. PC slices were prepared by cutting along three different nearly orthogonal planes (transverse, parasagittal, and longitudinal), and epileptiform discharges were imaged with a voltage-sensitive fluorescent dye. Interictal-like epileptiform activity was enabled by either a kindling-like induction process or disinhibition with bicuculline. The pattern of discharge onset was very similar in slices cut in different planes. As described previously in transverse PC slices, discharges were initiated in the endopiriform nucleus (En) and adjoining regions in a two-stage process, starting with low-amplitude “plateau activity” at one site and leading to an accelerating depolarization and discharge onset at another nearby site. The similar pattern of onset in slices of various orientations indicates that the local circuitry and neuronal properties in and around the En, rather than long-range fibers, assume dominant roles in the initiation of epileptiform activity. Subtle variations in the onset site indicate that interneurons can fine tune the site of discharge onset. In contrast to the mode of onset, discharge propagation showed striking variations. In longitudinal slices, where rostrocaudal association fibers are best preserved, discharge propagation resembled in vivo seizure activity in the following respects: propagation was as rapid as in vivo and about two to three times faster than in other slices; discharges jumped abruptly between the En and PC; and discharges had large amplitudes in superficial layers of the PC. Cuts in longitudinal slices that partially separated the PC from the En eliminated these unique features. These results help clarify why epileptiform activity differs between in vitro and in vivo experiments and suggest that rostrocaudal pyramidal cell association fibers play a major role in the propagation of discharges in the intact brain. The longitudinal PC slice, which best preserves these fibers, is ideally suited for the study their role.

Pharmacognostical Standardization, Isolation of Phytoconstituents (β-sitosterol), HPTLC analysis of extracts of Operculina turpethum (Linn.) roots and evaluation of cytotoxic, in vitro & in vivo anti-inflammatory activities

2021 ◽  
Vol 18 ◽  
Author(s):  
Akash Ved ◽  
Shweta Gupta ◽  
Namrata Singh ◽  
Karuna S. Shukla ◽  
Om Prakash ◽  
...  
Keyword(s):  
Column Chromatography ◽  
Inflammatory Activity ◽  
Control Group ◽  
Albino Rats ◽  
Cell Viability Assay ◽  
Edema Formation ◽  
Egg Albumin ◽  
Anti Inflammatory

Background: Operculina turpethum (Linn.) Silva Manso, family- convolvulaceae, is an important plant in Indian conventional system of medicine which is extensively employed by different tribes in many countries to cure edema and painful conditions like arthritis, back pain; hyperlipidemia, diabetes mellitus, liver disorders, skin disorders and to regulate bowel functions. Objective: The roots of O. turpethum (Linn.) was subjected to physicochemical, phytochemical standardization, the chromatographic separation which was accomplished by column chromatography, TLC, and HPTLC, further, the acute toxicity, cytotoxic and anti-inflammatory activities of Operculina turpethum roots were estimated by in vivo and in vitro models. Materials and Methods: This study includes percentage yield of extraction, organoleptic evaluation along with the analysis of its physicochemical investigations & preliminary phytochemical estimation. The isolation of active phytoconstituents was done by column chromatography, and the isolated compound was then exposed to TLC and HPTLC analysis. Cytotoxic activity was tested by WST-1 based cell viability assay on HepG2 cells. Anti-inflammatory activity of methanol extract (ME) was evaluated against inflammation occur by both in vitro and in vivo method. Results: The methanolic extract exhibited the presence of most of the phytoconstituents out of all the extracts, the phytoconstituent phytosterol, i.e., β-sitosterol was isolated by column chromatography, identified and quantified by TLC and HPTLC, which is liable for anti-inflammatory activity. The amount of β-sitosterol was estimated to be 14.09 µg in 10.00 mg fraction of MEOT. MEOT is devoid of toxicity up to 2000 mg/kg in Wistar albino rats. It was analysed that in vitro anti-inflammatory activity of MEOT by egg albumin denaturation method exhibited a incredible decrement in turbidity and increasing the percentage inhibition of albumin denaturation (60.52%) in MEOT treated group as compared with control group. In egg albumin-induced edema in rats, MEOT at the dose of 400 mg/kg reduced the edema formation (3.03 ± 0.02) induced by egg albumin at 4th h. In cotton pellet-induced granuloma in rats, MEOT at the dose of 400 mg/kg displayed maximum granuloma inhibition (51.06%) which is similar to that of indomethacin. Conclusion: From the obtained findings it is confirmed that O. turpethum contains β-sitosterol which is responsible for potent anti-inflammatory activity without causing cytotoxicity to the plant. The results suggested that ME of O. turpethum roots had high potential for application as an anti-inflammatory agent. The recognization and confirmation of the plant can be obtaineded from the study and will present data which is aidful in determining the quality and purity of a crude drug which further helps in preventing its adulteration.

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