scholarly journals Effect of hyperphenylalaninaemia on lipid synthesis from ketone bodies by rat brain

1976 ◽  
Vol 154 (2) ◽  
pp. 319-325 ◽  
Author(s):  
M S. Patel ◽  
O E. Owen
Keyword(s):  
Rat Brain ◽  
Ketone Bodies ◽  
Brain Slices ◽  
Lipid Synthesis ◽  
Coa Transferase ◽  
Old Rats ◽  
And Function ◽  
Developing Rat

The effect of hyperphenylalaninaemia on the metabolism of ketone bodies in vivo and in vitro by developing rat brain was investigated. The incorporation in vivo of [14C]acetoacetate into cerebral lipids was decreased by both chronic (for 3 days) and acute (for 6h) hyperphenylalaninaemia induced by injecting phenylalanine into 1-week-old rats. In studies in vitro it was observed that the incorporation of the radioactivity from [14C]acetoacetate and 3-hydroxy[14C]butyrate into cerebral lipids was inhibited by phenyl-pyruvate, but not by phenylalanine. Phenylpyruvate also inhibited the incorporation of 3H from 3H2O into lipids by brain slices metabolizing either 3-hydroxybutyrate or acetoacetate in the presence of glucose. These findings suggest that the decrease in the incorporation in vivo of [14C]acetoacetate into cerebral lipids in hyperphenylalaninaemic rats is most likely caused by phenylpyruvate and not by phenylalanine. Phenylpyruvate as well as phenylalanine had no inhibitory effects on ketone-body-catabolizing enzymes, namely 3-hydroxybutyrate dehydrogenase, 3-oxo acid CoA-transferase and acetoacetyl-CoA thiolase, in rat brain. Phenylpyruvate but not phenylalanine inhibited the activity of the 2-oxoglutarate dehydrogenase complex from rat and human brain. These findings suggest that the metabolism of ketone bodies is impaired in brains of untreated phenylketonuric patients, and in turn may contribute to the diminution of mental development and function associated with phenylketonuria.

scholarly journals Phosphorylation-dependent interaction of the synaptic vesicle proteins cysteine string protein and synaptotagmin I

2002 ◽  
Vol 364 (2) ◽  
pp. 343-347 ◽  
Author(s):  
Gareth J.O. EVANS ◽  
Alan MORGAN
Keyword(s):  
Rat Brain ◽  
Direct Interaction ◽  
Secretory Vesicle ◽  
Brain Membrane ◽  
Synaptotagmin I ◽  
Phosphorylated Form ◽  
Order Of Magnitude ◽  
And Function

The secretory vesicle cysteine string proteins (CSPs) are members of the DnaJ family of chaperones, and function at late stages of Ca2+-regulated exocytosis by an unknown mechanism. To determine novel binding partners of CSPs, we employed a pull-down strategy from purified rat brain membrane or cytosolic proteins using recombinant hexahistidine-tagged (His6-)CSP. Western blotting of the CSP-binding proteins identified synaptotagmin I to be a putative binding partner. Furthermore, pull-down assays using cAMP-dependent protein kinase (PKA)-phosphorylated CSP recovered significantly less synaptotagmin. Complexes containing CSP and synaptotagmin were immunoprecipitated from rat brain membranes, further suggesting that these proteins interact in vivo. Binding assays in vitro using recombinant proteins confirmed a direct interaction between the two proteins and demonstrated that the PKA-phosphorylated form of CSP binds synaptotagmin with approximately an order of magnitude lower affinity than the non-phosphorylated form. Genetic studies have implicated each of these proteins in the Ca2+-dependency of exocytosis and, since CSP does not bind Ca2+, this novel interaction might explain the Ca2+-dependent actions of CSP.

Acute hypoxia induces elevation of ornithine decarboxylase activity in neonatal rat brain slices

1995 ◽  
Vol 7 (3) ◽  
pp. 385 ◽  
Author(s):  
LD Longo ◽  
S Packianathan
Keyword(s):  
Rat Brain ◽  
Ornithine Decarboxylase ◽  
Bovine Serum ◽  
Brain Slice ◽  
Brain Slices ◽  
Neonatal Rat ◽  
Newborn Rat ◽  
Rat Brain Slice

Recent studies in vivo have demonstrated that ornithine decarboxylase (ODC) activity in the fetal rat brain is elevated 4-5-fold by acute maternal hypoxia. This hypoxic-associated increase is seen in the rat brain in both the newborn and the adult. Because of the intimate involvement of ODC in transcription and translation, as well as in growth and development, it is imperative that the manner in which hypoxia affects the regulation of this enzyme be better understood. In order to achieve this, a brain preparation in vitro was required to eliminate the confounding effects of the dam on the fetal and newborn brain ODC activity in vivo. Therefore, brain slices from 3-4-day-old (P-3) newborn rats were utilized to test the hypothesis that ODC activity increases in response to hypoxia in vitro. Cerebral slices from the P-3 rat pups were allowed to equilibrate and recover in artificial cerebrospinal fluid (ACSF) continuously bubbled with a mixture of 95% O2 and 5% CO2 for 1 h before beginning hypoxic exposures. Higher basal ODC activities were obtained by treating the slices with 0.03% fetal bovine serum (FBS) and 0.003% bovine serum albumin (BSA), rather than with ACSF alone. Hypoxia was induced in the slices by replacing the gas with 40%, 21%, 10%, or 5% O2, all with 5% CO2 and balance N2. With FBS and BSA treatment, ODC activity was maintained at about 0.15-0.11 nM CO2 mg-1 protein h-1 throughout the experiment, which was 2-3-fold higher than that without FBS and BSA. ODC activity increased significantly and peaked between 1 h and 2 h after initiation of hypoxia. For instance, with 21% O2, ODC activity increased approximately 1.5-fold at 1 h and approximately 2-fold at 2 h. These studies demonstrate that: (1) the hypoxic-induced increases observed in vivo in the fetal and newborn rat brain ODC activity can be approximated in a newborn rat brain slice preparation in vitro; (2) newborn rat brain slice preparations may provide an alternative to methods in vivo or cell culture methods for studying the regulation of acute hypoxic-induced enzymes; and (3) high, stable baseline ODC activities in brain slices suggest that the cells in the slice are capable of active metabolism if FBS and BSA are available to mimic conditions in vivo.

scholarly journals Cloning of rat brain succinyl-CoA:3-oxoacid CoA-transferase cDNA. Regulation of the mRNA in different rat tissues and during brain development

1987 ◽  
Vol 248 (3) ◽  
pp. 853-857 ◽  
Author(s):  
M K Ganapathi ◽  
M Kwon ◽  
P M Haney ◽  
C McTiernan ◽  
A A Javed ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Rat Brain ◽  
Ketone Bodies ◽  
Rat Kidney ◽  
Relative Rate ◽  
Cdna Clones ◽  
Rat Tissues ◽  
Transferase Activity ◽  
Coa Transferase ◽  
Old Rats

3-Oxoacid CoA-transferase, which catalyses the first committed step in the oxidation of ketone bodies, is uniquely regulated in developing rat brain. Changes in 3-oxoacid CoA-transferase activity in rat brain during the postnatal period are due to changes in the relative rate of synthesis of the enzyme. To study the regulation of this enzyme, we identified, with a specific polyclonal rabbit anti-(rat 3-oxoacid CoA-transferase), two positive cDNA clones (approx. 800 bp) in a lambda gtll expression library, constructed from poly(A)+ RNA from brains of 12-day-old rats. One of these clones (lambda CoA3) was subcloned into M13mp18 and subjected to further characterization. Labelled single-stranded probes prepared by primer extension of the M13mp18 recombinant hybridized to a 3.6 kb mRNA. Rat brain mRNA enriched by polysome immunoadsorption for a single protein of size 60 kDa which corresponds to the precursor form of 3-oxoacid CoA-transferase was also found to be similarly enriched for the hybridizable 3.6 kb mRNA complementary to lambda CoA3. Affinity-selected antibody to the lambda CoA3 fusion protein inhibited 3-oxoacid CoA-transferase activity present in rat brain mitochondrial extracts. The 3.6 kb mRNA for 3-oxoacid CoA-transferase was present in relative abundance in rat kidney and heart, to a lesser extent in suckling brain and mammary gland and negligible in the liver. The specific mRNA was also found to be 3-fold more abundant in the brain from 12-day-old rats as compared with 18-day-old foetuses and adult rats, corresponding to the enzyme activity and relative rate of synthesis profile during development. These data suggest that 3-oxoacid CoA-transferase enzyme activity is regulated at a pretranslational level.

scholarly journals Fas/CD95/APO-1 Can Function as a Death Receptor for Neuronal Cells in Vitro and in Vivo and is Upregulated Following Cerebral Hypoxic-Ischemic Injury to the Developing Rat Brain

2006 ◽  
Vol 10 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Ursula Felderhoff-Mueser ◽  
Deanna L. Taylor ◽  
Kirsty Greenwood ◽  
Mary Kozma ◽  
Dietger Stibenz ◽  
...  
Keyword(s):  
Rat Brain ◽  
Neuronal Cells ◽  
Death Receptor ◽  
Ischemic Injury ◽  
Developing Rat ◽  
Hypoxic Ischemic Injury

scholarly journals Spindle-Like Thalamocortical Synchronization in a Rat Brain Slice Preparation

2000 ◽  
Vol 84 (2) ◽  
pp. 1093-1097 ◽  
Author(s):  
Virginia Tancredi ◽  
Giuseppe Biagini ◽  
Margherita D'Antuono ◽  
Jacques Louvel ◽  
René Pumain ◽  
...  
Keyword(s):  
Rat Brain ◽  
Kynurenic Acid ◽  
Brain Slice ◽  
Excitatory Amino Acid ◽  
Brain Slices ◽  
Reticular Nucleus ◽  
Antidromic Responses ◽  
Rat Brain Slice

We obtained rat brain slices (550–650 μm) that contained part of the frontoparietal cortex along with a portion of the thalamic ventrobasal complex (VB) and of the reticular nucleus (RTN). Maintained reciprocal thalamocortical connectivity was demonstrated by VB stimulation, which elicited orthodromic and antidromic responses in the cortex, along with re-entry of thalamocortical firing originating in VB neurons excited by cortical output activity. In addition, orthodromic responses were recorded in VB and RTN following stimuli delivered in the cortex. Spontaneous and stimulus-induced coherent rhythmic oscillations (duration = 0.4–3.5 s; frequency = 9–16 Hz) occurred in cortex, VB, and RTN during application of medium containing low concentrations of the K+ channel blocker 4-aminopyridine (0.5–1 μM). This activity, which resembled electroencephalograph (EEG) spindles recorded in vivo, disappeared in both cortex and thalamus during application of the excitatory amino acid receptor antagonist kynurenic acid in VB ( n = 6). By contrast, cortical application of kynurenic acid ( n = 4) abolished spindle-like oscillations at this site, but not those recorded in VB, where their frequency was higher than under control conditions. Our findings demonstrate the preservation of reciprocally interconnected cortical and thalamic neuron networks that generate thalamocortical spindle-like oscillations in an in vitro rat brain slice. As shown in intact animals, these oscillations originate in the thalamus where they are presumably caused by interactions between RTN and VB neurons. We propose that this preparation may help to analyze thalamocortical synchronization and to understand the physiopathogenesis of absence attacks.

scholarly journals Carbodiimide as a tissue fixative in histamine immunohistochemistry and its application in developmental neurobiology.

1988 ◽  
Vol 36 (3) ◽  
pp. 259-269 ◽  
Author(s):  
P Panula ◽  
O Häppölä ◽  
M S Airaksinen ◽  
S Auvinen ◽  
A Virkamäki
Keyword(s):  
Rat Brain ◽  
Nerve Fibers ◽  
Immunohistochemical Method ◽  
Dot Blot ◽  
Culture Dish ◽  
Long Fibers ◽  
Developing Rat ◽  
Strong Immunoreactivity

The object of this study was to develop an immunohistochemical method that could be used to study neuronal histamine, especially in nerve fibers and terminals where most previous methods have not been applicable. Three new antisera were produced in rabbits against conjugated histamine, and the fixative used in conjugation, 1-ethyl-3(3-diamethylaminopropyl)-carbodiimide (EDCDI), was used in tissue fixation and compared to paraformaldehyde. Specificity of the antisera was established with dot-blot tests on nitrocellulose, with blocking controls and affinity-purified antibodies. EDCDI appeared to be superior to paraformaldehyde as a fixative, and histamine-immunoreactive nerve cells were visualized in developing rat brain during late fetal development from embryonal day 12. By the second postnatal week, the distribution of histamine-immunoreactive neurons in rat brain had reached the adult pattern and immunoreactive nerve fibers were seen in many areas. Posterior hypothalamic neurons from newborn rat in vitro showed strong immunoreactivity for histamine and developed long varicose fibers, which covered the culture dish by the end of the fourth week in vitro. Fixation with EDCDI also allowed detection of histamine in gastric enterochromaffin-like cells and mast cells in rat. The results suggest that the histamine-containing neuron system in rat brain develops during the late fetal and early postnatal periods, and that immunoreactive neurons develop long fibers both in vivo and in vitro.

scholarly journals NMDA Receptors in Astrocytes: In Search for Roles in Neurotransmission and Astrocytic Homeostasis

2019 ◽  
Vol 20 (2) ◽  
pp. 309 ◽  
Author(s):  
Katarzyna Skowrońska ◽  
Marta Obara-Michlewska ◽  
Magdalena Zielińska ◽  
Jan Albrecht
Keyword(s):  
Nmda Receptors ◽  
Brain Slices ◽  
Cultured Astrocytes ◽  
Specific Proteins ◽  
Homeostatic Function ◽  
Inward Rectifying Potassium Channel ◽  
And Function

Studies of the last two decades have demonstrated the presence in astrocytic cell membranes of N-methyl-d-aspartate (NMDA) receptors (NMDARs), albeit their apparently low abundance makes demonstration of their presence and function more difficult than of other glutamate (Glu) receptor classes residing in astrocytes. Activation of astrocytic NMDARs directly in brain slices and in acutely isolated or cultured astrocytes evokes intracellular calcium increase, by mutually unexclusive ionotropic and metabotropic mechanisms. However, other than one report on the contribution of astrocyte-located NMDARs to astrocyte-dependent modulation of presynaptic strength in the hippocampus, there is no sound evidence for the significant role of astrocytic NMDARs in astrocytic-neuronal interaction in neurotransmission, as yet. Durable exposure of astrocytic and neuronal co-cultures to NMDA has been reported to upregulate astrocytic synthesis of glutathione, and in this way to increase the antioxidative capacity of neurons. On the other hand, overexposure to NMDA decreases, by an as yet unknown mechanism, the ability of cultured astrocytes to express glutamine synthetase (GS), aquaporin-4 (AQP4), and the inward rectifying potassium channel Kir4.1, the three astroglia-specific proteins critical for homeostatic function of astrocytes. The beneficial or detrimental effects of astrocytic NMDAR stimulation revealed in the in vitro studies remain to be proven in the in vivo setting.

scholarly journals Non-signalling energy use in the developing rat brain

2016 ◽  
Vol 37 (3) ◽  
pp. 951-966 ◽  
Author(s):  
Elisabeth Engl ◽  
Renaud Jolivet ◽  
Catherine N Hall ◽  
David Attwell
Keyword(s):  
Oxygen Consumption ◽  
Information Processing ◽  
Rat Brain ◽  
Energy Use ◽  
Brain Slices ◽  
Lipid Synthesis ◽  
Processing Power ◽  
Mature Brain ◽  
Rate Of Oxygen Consumption

Energy use in the brain constrains its information processing power, but only about half the brain's energy consumption is directly related to information processing. Evidence for which non-signalling processes consume the rest of the brain's energy has been scarce. For the first time, we investigated the energy use of the brain's main non-signalling tasks with a single method. After blocking each non-signalling process, we measured oxygen level changes in juvenile rat brain slices with an oxygen-sensing microelectrode and calculated changes in oxygen consumption throughout the slice using a modified diffusion equation. We found that the turnover of the actin and microtubule cytoskeleton, followed by lipid synthesis, are significant energy drains, contributing 25%, 22% and 18%, respectively, to the rate of oxygen consumption. In contrast, protein synthesis is energetically inexpensive. We assess how these estimates of energy expenditure relate to brain energy use in vivo, and how they might differ in the mature brain.

Sign in / Sign up

Export Citation Format

Share Document