Halothane Modulates Thermosensitive Hypothalamic Neurons in Rat Brain Slices

1995 ◽  
Vol 83 (6) ◽  
pp. 1241-1253 ◽  
Author(s):  
Neil E. Farber ◽  
Jeffrey E. Schmidt ◽  
John P. Kampine ◽  
William T. Schmeling
Keyword(s):  
Rat Brain ◽  
Brain Slices ◽  
Anterior Hypothalamus ◽  
Spontaneous Firing ◽  
Preoptic Region ◽  
Tissue Slices ◽  
Hypothalamic Neurons ◽  
Hypothalamic Tissue

Abstract Background In vivo, halothane alters spontaneous firing in and thermosensitivity of neurons in the preoptic region of the anterior hypothalamus. To better understand the mechanisms by which halothane specifically disrupts normal thermoregulation, this investigation examined the effects of halothane on thermosensitive preoptic region neurons in isolated hypothalamic tissue slices.

Sigma receptors mediate potent neuroprotection in vivo and inhibit neuronal depolarisation and swelling in rat brain slices

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S468-S468
Author(s):  
Jennifer K Callaway ◽  
Christine Molnar ◽  
Song T Yao ◽  
Bevyn Jarrott ◽  
R David Andrew
Keyword(s):  
Rat Brain ◽  
Brain Slices ◽  
Sigma Receptors

Intracellular pH in rat brain in vivo and in brain slices

1992 ◽  
Vol 70 (S1) ◽  
pp. S269-S277 ◽  
Author(s):  
Joseph C. LaManna ◽  
J. Keven Griffith ◽  
Boris R. Cordisco ◽  
Chii-Wann Lin ◽  
W. David Lust
Keyword(s):  
Cardiac Arrest ◽  
Rat Brain ◽  
Intracellular Ph ◽  
Brain Slice ◽  
Spatial Information ◽  
Brain Slices ◽  
Neutral Red ◽  
Hydrogen Ion ◽  
Sodium Hydrogen

Intracellular pH can be measured quantitatively in rat brain in vivo and in vitro using spectrophotometric detection of the vital dye neutral red. This method preserves spatial information and is compatible with microhistochemistry. The intracellular pH indicated by this method is in close agreement with that indicated by 31P-NMR spectroscopy. During ischemia, intracellular acidification is correlated with tissue lactate accumulation. The spatial distribution of pH values becomes more heterogeneous as the tissue becomes more acidic. Resuscitation from total cerebral ischemia produced by cardiac arrest results in rapid intracellular realkalinization. This realkalinization is at least partially inhibited by amiloride pretreatment. Some neuronal populations, especially in the hippocampal CA1 and CA4 regions, may become more acidic during ischemia and realkalinize more slowly after reperfusion than other tissue regions. The intracellular pH of hippocampal brain slice preparations is more alkaline than expected from in vivo studies. The intracellular pH of the brain slice can be acidified to near neutrality by specific inhibitors of the sodium/hydrogen ion exchanger.Key words: hippocampal brain slice, intracellular pH, neutral red, cardiac arrest and resuscitation, sodium/hydrogen ion exchanger.

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 The effects of Cirazoline, an alpha-1 adrenoreceptor agonist, on the firing rates of thermally classified anterior hypothalamic neurons in rat brain slices

2008 ◽  
Vol 1193 ◽  
pp. 93-101 ◽  
Author(s):  
Ted E. Imbery ◽  
Mitra S. Irdmusa ◽  
Andrew P. Speidell ◽  
Mark S. Streer ◽  
John D. Griffin
Keyword(s):  
Rat Brain ◽  
Brain Slices ◽  
Hypothalamic Neurons ◽  
Firing Rates

scholarly journals Human POMC processing in vitro and in vivo revealed by quantitative peptidomics

2018 ◽  
Author(s):  
Peter Kirwan ◽  
Richard Kay ◽  
Bas Brouwers ◽  
Vicente Herranz-Perez ◽  
Magdalena Jura ◽  
...  
Keyword(s):  
Body Weight ◽  
Human Obesity ◽  
Hypothalamic Neurons ◽  
Melanocyte Stimulating Hormone ◽  
Liquid Chromatography Tandem Mass ◽  
Tandem Mass Spectroscopy ◽  
Hypothalamic Tissue ◽  
Human Specific

ABSTRACTHuman obesity can result from the aberrant production or processing of proopiomelanocortin (POMC) in hypothalamic neurons, but it is unclear which human POMC-derived peptides are most relevant to body weight regulation. To address this question, we analysed both hypothalamic neurons derived from human pluripotent stem cells (hPSCs) and primary human hypothalamic tissue using quantitative liquid chromatography tandem mass spectroscopy (LC-MS/MS). In both in vitro- and in vivo-derived samples, we found that POMC was processed into β-melanocyte stimulating hormone (β-MSH), whose existence in the human brain has been controversial. β-MSH and desacetyl α-MSH (d-α-MSH) were produced at roughly equimolar concentrations and in vast excess to acetylated α-MSH (5-to 200-fold), suggesting that the importance of both d-α-MSH and β-MSH to human obesity has been underestimated. Since body weight is sensitive to changes in MSH concentration, we asked whether hPSC-derived hypothalamic neurons could provide mechanistic insights into the processing and secretion of MSH peptides. We found that cultured human hypothalamic neurons appropriately trafficked POMC and its derivatives, and robustly (P<0.0001) secreted them when depolarised. Furthermore, the adipocyte-derived hormone leptin significantly (P<0.01) promoted their production of both d-α-MSH and β-MSH. These results establish hPSC-derived hypothalamic neurons as a model system for studying human-specific aspects of POMC processing that might be therapeutically harnessed to treat obesity.

Regional interactions between thermosensitive neurons in diencephalic slices

1992 ◽  
Vol 263 (3) ◽  
pp. R670-R678 ◽  
Author(s):  
J. B. Dean ◽  
M. L. Kaple ◽  
J. A. Boulant
Keyword(s):  
Rat Brain ◽  
Brain Slices ◽  
Effect Of Temperature ◽  
Cold Sensitivity ◽  
Neuronal Responses ◽  
Tissue Slices ◽  
Lateral Border ◽  
Temperature Changes ◽  
Extracellular Recordings ◽  
Stimulation Of

Rat brain slices were used to investigate regional interactions between thermosensitive neurons in different diencephalic regions. Horizontal tissue slices rested over three thermodes. This permitted independent thermal stimulation of rostral, middle, and caudal regions. Thermocouples measured tissue temperatures in these three locations, and extracellular recordings measured neuronal responses to temperature changes both locally (at the site of the recorded neuron) and in remote regions of the slice. Many of the neurons that were sensitive to remote temperatures were located near the lateral border of the diencephalic nuclei, especially in the perifornical area. All neurons displaying remote thermosensitivity also displayed local thermosensitivity. These neurons usually showed opposite responses to remote and local temperatures; i.e., most of these neurons were locally warm sensitive but showed cold sensitivity to remote temperatures. These findings indicate that thermosensitive synaptic networks extend throughout the diencephalon and may explain the effect of temperature on a variety of homeostatic systems.

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 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.

Sign in / Sign up

Export Citation Format

Share Document