Spectrophotometry of b-type cytochromes in rat brain in vivo and in vitro

Terminal oxidase inhibitors such as cyanide (CN) and carbon monoxide (CO) produce different absorption changes in the intact brain, suggesting different mitochondrial responses to the inhibitors. In the present study, the nature of the cytochromes involved in CO and CN responses in vivo was investigated by low-temperature spectroscopy of rat brain, frozen in situ, and of preparations of brain homogenate and isolated mitochondria. Comparison of the spectra from different preparations at the high resolution afforded by low-temperature spectroscopy indicated that absorption responses to CO in vivo originated from mitochondrial b cytochromes. Further detailed spectral analysis of mitochondrial preparations revealed three CN-insensitive b cytochromes in nonsynaptic brain mitochondria; one cytochrome could be reduced by succinate in the presence of CN, the second could be reduced by succinate plus ATP, and the third could be reduced only by anaerobiosis. The spectral characteristics of the mitochondrial b cytochromes, when compared with spectra from CO-exposed brain tissue frozen in situ, strongly implicated the energy-dependent cytochrome b in the oxidation-reduction (redox) responses caused by CO in vivo.

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In vivo activity of glutaminase in the brain of hyperammonaemic rats measured by 15N nuclear magnetic resonance

Biochemical Journal ◽

10.1042/bj3050329 ◽

1995 ◽

Vol 305 (1) ◽

pp. 329-336 ◽

Cited By ~ 38

Author(s):

K Kanamori ◽

B D Ross

Keyword(s):

Brain Homogenate ◽

Inhibitory Effect ◽

Intact Brain ◽

Strong Inhibitory Effect ◽

Glutamine Synthesis ◽

Gaba Synthesis ◽

The Brain

The in vivo activity of phosphate-activated glutaminase (PAG) was measured in the brain of hyperammonaemic rat by 15N n.m.r. Brain glutamine was 15N-enriched by intravenous infusion of 15NH4+ until the concentration of [5-15N]glutamine reached 6.1 mumol/g. Further glutamine synthesis was inhibited by intraperitoneal injection of methionine-DL-sulphoximine, an inhibitor of glutamine synthetase, and the infusate was changed to 14NH4+ during observation of decrease in brain [5-15N]glutamine due to PAG and other glutamine utilization pathways. Progressive decrease in brain [5-15N]glutamine, PAG-catalysed production of 15NH4+ and its subsequent assimilation into glutamate by glutamate dehydrogenase were monitored in vivo by 15N n.m.r. Brain [5-15N]glutamine (15N enrichment of 0.35-0.50) decreased at a rate of 1.2 mumol/h per g of brain. The in vivo PAG activity, determined from the observed rate and the quantity of 15NH4+ produced and subsequently assimilated into glutamate and aspartate, was 0.9-1.3 mumol/h per g. This activity is less than 1.1% of the reported activity in vitro measured in rat brain homogenate at a 10 mM concentration of the activator Pi. Inhibition by ammonia (brain level 1.4 mumol/g) alone does not account for the observed low activity in vivo. The result strongly suggests that, in intact brain, PAG activity is maintained at a low level by a suboptimal in situ concentration of Pi and the strong inhibitory effect of glutamate. The observed PAG activity in vivo is lower than the reported in vivo activity of glutamate decarboxylase which converts glutamate into gamma-aminobutyrate (GABA). The result suggests that PAG-catalysed hydrolysis of glutamine is not the sole provider of glutamate used for GABA synthesis.

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Bispyridinium Oximes As Antidotal Treatment of Cyclosarin Poisoning—In Vitro and In Vivo Testing

International Journal of Toxicology ◽

10.1080/10915810500366567 ◽

2005 ◽

Vol 24 (6) ◽

pp. 399-402 ◽

Cited By ~ 7

Author(s):

Lucie Bartosova ◽

Kamil Kuca ◽

Daniel Jun ◽

Gabriela Kunesova

Keyword(s):

Rat Brain ◽

Organophosphorus Compounds ◽

Brain Homogenate ◽

Chemical Structures ◽

Hi 6 ◽

In Vivo Testing ◽

Acetylcholinesterase Enzyme ◽

Enzyme Source

The mechanism of intoxication with organophosphorus compounds, including highly toxic nerve agents and less toxic pesticides, is based on the formation of irreversibly inhibited acetylcholinesterase, which causes cumulation of neuromediator acetylcholine in synaptic clefts and subsequent overstimulation of cholinergic receptors, that is followed by a generalized cholinergic crisis. Nerve agent poisoning is conventionally treated using a combination of a cholinolytic (atropine mostly) to counteract the accumulation of acetylcholine and acetylcholinesterase reactivators (pralidoxime or obidoxime) to reactivate inhibited acetylcholinesterase. In this study of cyclosarin poisoning treatment, oximes of different chemical structures (obidoxime, HI-6, BI-6, and HS-6) were tested in vitro on rat brain acetylcholinesterase (enzyme source: rat brain homogenate), and afterwards, they were tested in vivo in equimolar doses, in mice and rats. The HI-6 oxime appeared to be the most effective oxime in vitro and in vivo.

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Effects of Aluminium on Rat Brain Mitochondria Bioenergetics: an In vitro and In vivo Study

Molecular Neurobiology ◽

10.1007/s12035-015-9650-z ◽

2016 ◽

Vol 54 (1) ◽

pp. 563-570 ◽

Cited By ~ 13

Author(s):

Javier Iglesias-González ◽

Sofía Sánchez-Iglesias ◽

Andrés Beiras-Iglesias ◽

Estefanía Méndez-Álvarez ◽

Ramón Soto-Otero

Keyword(s):

Rat Brain ◽

Brain Mitochondria ◽

In Vivo Study ◽

Rat Brain Mitochondria

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In vitro and in vivo effect of chloropromazine, imipramine and lithium chloride on monoamine oxidase activity in rat brain mitochondria

Bioscience Reports ◽

10.1007/bf01116862 ◽

1987 ◽

Vol 7 (9) ◽

pp. 701-704 ◽

Cited By ~ 5

Author(s):

Maitreyi Nag ◽

Namita Nandi

Keyword(s):

Monoamine Oxidase ◽

Rat Brain ◽

Dose Level ◽

Lithium Chloride ◽

Oxidase Activity ◽

Brain Mitochondria ◽

Monoamine Oxidase Activity ◽

Mitochondrial Monoamine Oxidase

Chloropromazine (CPZ) and imipramine at a concentration of 1×10−3 M inhibit rat brain mitochondrial monoamine oxidase activity in vitro by 70 and 55% respectively, while lithium, even at a concentration of 0.05 M, inhibits the activity of this enzyme very negligibly (4%). In vivo, these drugs at a dose level of 56 mg CPZ, 76 mg Jimipramine and 76 mg lithium chloride/Kg body wt., did not cause any observable variation from normal in brain mitochondrial monoamine oxidase activity.

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Differences in brain cytochrome responses to carbon monoxide and cyanide in vivo

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.3.1277 ◽

1987 ◽

Vol 62 (3) ◽

pp. 1277-1284 ◽

Cited By ~ 20

Author(s):

C. A. Piantadosi ◽

A. L. Sylvia ◽

F. F. Jobsis-Vandervliet

Keyword(s):

Carbon Monoxide ◽

Rat Brain ◽

Cytochrome B ◽

Brain Slices ◽

Oxidation Reduction ◽

Transport Inhibitors ◽

Cytochrome Oxidation ◽

Primary Tissue

Cytochrome oxidation-reduction responses to two mitochondrial electron transport inhibitors, carbon monoxide (CO) and cyanide (CN), were studied in the intact brains of fluorocarbon-circulated rats. In vivo reflectance spectrophotometry indicated that cortical b-type cytochromes (564 nm) were highly resistant to reduction by CN in the presence of O2 but showed reduction responses to the administration of 1–5% CO in 90% O2. In contrast, cyanide-sensitive cytochromes aa3 (605 nm) and c + c1 (551 nm) did not increase their reduction levels during exposure to 5% CO in 90% O2. The in vivo CO-mediated b-cytochrome reduction responses did not occur after pretreatment with the cytochrome b inhibitor, antimycin A. Transmission spectrophotometry of superfused hemoglobin-free rat brain slices confirmed cortical b-type cytochromes to be CN-resistant in the presence of O2. Another cytochrome absorbing at 445 nm also was resistant to reduction by 1-mM cyanide in vitro, but it could be reduced anaerobically. The reduced 445-nm cytochrome bound CO in the presence of cyanide. We postulate that this CN-resistant CO binding component might account for in vivo cytochrome aa3-CO interactions and directly or indirectly modulate cytochrome b reduction responses to CO. In any event, the spectral data indicate different primary tissue target sites for CO and CN in living rat brain and also suggest different bioenergetic consequences of exposure to the two agents.

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In vitro and in vivo effect of organophosphate pesticides on monoamine oxidase activity in rat brain

Bioscience Reports ◽

10.1007/bf01116753 ◽

1987 ◽

Vol 7 (10) ◽

pp. 801-803 ◽

Cited By ~ 3

Author(s):

Maitreyi Nag ◽

Namita Nandi

Keyword(s):

Monoamine Oxidase ◽

Rat Brain ◽

Oxidase Activity ◽

Brain Mitochondria ◽

Significant Inhibition ◽

Organophosphate Pesticides ◽

Monoamine Oxidase Activity ◽

Mao Activity

The effects of some organophosphate pesticides, e.g. lebaycid, metacid and metasystox on the monoamine oxidase (MAO) activity in rat brain mitochondria have been studied. These pesticides cause significant inhibition of MAO activity in vitro but have negligible effects on its activity in vivo.

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Effect of phencyclidine on oxygen consumption of rat brain mitochondria in vitro and in vivo

Biochemical Pharmacology ◽

10.1016/0006-2952(73)90033-6 ◽

1973 ◽

Vol 22 (13) ◽

pp. 1661-1665 ◽

Cited By ~ 8

Author(s):

S. Millo ◽

A. Chari-Bitron

Keyword(s):

Oxygen Consumption ◽

Rat Brain ◽

Brain Mitochondria ◽

Rat Brain Mitochondria

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In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083035 ◽

1978 ◽

Vol 36 (2) ◽

pp. 434-435

Author(s):

D. Reis ◽

B. Vian ◽

J. C. Roland

Keyword(s):

Cell Wall ◽

Self Assembly ◽

Plant Cell Wall ◽

Higher Plants ◽

Three Dimensional ◽

Cytochemical Study ◽

Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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