Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments were done in order to test the hypothesis that enteric neurons project to the pancreas and can modify pancreatic endocrine and exocrine activity. Injections of the retrograde tracer Fluoro-Gold (FG) into the rat pancreas labeled neurons in the myenteric plexus of the antrum of the stomach and in the first 6 cm of the duodenum. A subset of myenteric neurons were found in both the antrum and duodenum that were doubly labeled by retrograde transport of FG and anti-serotonin (5-HT) sera; therefore, some of the enteric neurons that innervate the pancreas are serotonergic. Within the pancreas, 5-HT-immunoreactivity was not found in any neuronal cell bodies; however, 5-HT-immunoreactive axons were observed. Varicose 5-HT-immunoreactive terminal axons were most commonly found in pancreatic ganglia. Anterograde tracers were microinjected into individual myenteric ganglia in order to determine the pancreatic targets of the enteric innervation. Following the microinjection of the B subunit of cholera toxin (B-CT) or 1,1", dioctadecyl-3,3,3',3'-tetramethylcarbocyanine (Dil) into myenteric ganglia in the duodenum, labeled fibers were found in the pancreatic parenchyma. B-CT-immunoreactive terminals were most commonly observed in pancreatic ganglia, suggesting that pancreatic ganglia are the major targets in the pancreas of the enteric innervation. Experiments were also performed physiologically to determine whether enteric stimuli can influence pancreatic exocrine or endocrine activity via a neural pathway. For this purpose enteric neurons were stimulated in vitro by luminal application of veratridine (Ver), and the metabolic activity of neurons, islet, and acinar cells was determined in attached segments of pancreas by measuring their cytochrome oxidase (CO) activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Innervation and regulation of the pancreas by neurons in the gut. 171 58

An improved device for potentiometry using magnetic circular dichroism spectroscopy has been developed and used to characterize the potentiometric behavior of solubilized beef heart cytochrome oxidase. In the absence of inhibitors, the electron affinity of cytochromes alpha and alpha 3 are indistinguishable and adequately described by the allosteric model of Nicholls and Peterson (Nicholls, P., and Peterson, L. C. (1972) Biochim. Biophys. Acta 357, 462-467). All of the cytochrome alpha can be accounted for as low spin heme throughout the titration. Cytochrome c present at 1:1, 2:1, and 4:1 stoichiometry with cytochrome alpha did not significantly affect the potentiometric behavior of alpha or chondroitinase alpha 3; at the 1:1 ratio the midpoint potential of cytochrome c was lowered by about 30 mV. In the presence of formate, azide and cyanide cytochrome alpha assumed approximately n = 1 behavior. However, the response of alpha 3 differed with each reagent and was particularly complex in the presence of azide. Fluoride produced very small changes in the potentiometric behavior suggesting that it may not be a ligand to cytochrome alpha 3. Possible deficiencies in the allosteric model are examined.
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PMID:Further characterization of the potentiometric behavior of cytochrome oxidase. Cytochrome alpha stays low spin during oxidation and reduction. 631 78

The postnatal development of direct thalamocortical projections from the zona incerta of the ventral thalamus to the whisker representation area of the rat primary somatosensory cortex was investigated. Cytoarchitectonic analysis based on Nissl staining, cytochrome oxidase histochemistry and immunohistochemistry for glutamic acid decarboxylase, GABA, parvalbumin and calbindin D28K revealed that the zona incerta can be clearly distinguished from surrounding diencephalic structures from the day of birth. Moreover, four distinct anatomical subdivisions of this nucleus were identified: the rostral, dorsal, ventral and caudal. Of these, the ventral subdivision is by far the most conspicuous, containing the highest density of neurons, and the highest levels of cytochrome oxidase, glutamate decarboxylase, GABA, parvalbumin and calbindin D28K. In contrast, the dorsal, rostral and caudal subdivisions contain fewer cells, lower levels of glutamic acid decarboxylase and GABA and very few parvalbumin-positive and calbindin-positive neurons. Small injections of rhodamine coated microspheres or Fluoro-gold in the primary somatosensory cortex of animals at different stages of development revealed the existence of retrogradely labeled neurons in the rostral and dorsal subdivisions of the zona incerta from postnatal day 1. At this age, retrogradely labeled cells were also found in the ventral lateral, ventral posterior medial, posterior medial, centrolateral, ventral medial and magnocellular subdivision of the medial geniculate nuclei of the dorsal thalamus. The density of the incertocortical projection reaches its maximum between the first and second postnatal weeks, decreasing subsequently, until an adult pattern of labeling is achieved. Tracer injections combined with immunohistochemistry revealed that the majority of the incertocortical projection derives from GABAergic neurons, implying a potentially inhibitory role for the incertocortical projection. These results demonstrate that the rat trigeminal system contains parallel thalamocortical pathways of opposite polarity, emerging from both the dorsal (glutamatergic, excitatory) and ventral (GABAergic, inhibitory) thalamus since the day of birth. As such, these findings suggest that, contrary to the classical notion, not only the dorsal but also the ventral thalamus may play a special role in both cortical maturation and function.
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PMID:Development of direct GABAergic projections from the zona incerta to the somatosensory cortex of the rat. 777 73

The effects of various glycolytic substrates and keto acid metabolites on the cytotoxic effects of cyanide have been studied with isolated rat hepatocytes. The sequence of cytotoxic events with 2 mM cyanide was an immediate inhibition of respiration followed by ATP depletion. Disruption of the plasma membrane occurred when 85-90% of ATP levels had been depleted. Fructose, dihydroxyacetone, glyceraldehyde, pyruvate, and alpha-ketoglutarate prevented cyanide-induced cytotoxicity and ATP depletion. Hepatocyte respiration was also restored by all except fructose. Fructose, unlike the others, also did not prevent cytotoxicity if added 30-60 min after cyanide. Fluoride, an inhibitor of the glycolytic enzyme enolase, prevented protection by fructose but not dihydroxyacetone or glyceraldehyde, suggesting that dihydroxyacetone and glyceraldehyde are cytoprotective by trapping cyanide, thereby restoring cytochrome oxidase activity and cellular ATP levels. Fructose, on the other hand, may be cytoprotective by supplying ATP through glycolysis. Hepatocytes isolated from fasted rats were five- to sevenfold more susceptible to cyanide-induced cytotoxicity. Furthermore, all glycogenic and gluconeogenic amino acids and carbohydrates were cytoprotective against cyanide toxicity toward fasted hepatocytes, suggesting that cellular energy stores determine their resistance to cyanide.
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PMID:Prevention of cyanide-induced cytotoxicity by nutrients in isolated rat hepatocytes. 794 May 42

Multiple injections of methamphetamine (mAMPH) cause degeneration of neurons in rat primary somatosensory cortex (Par1). These degenerating cells can be labeled histochemically with the fluorochrome dye, Fluoro-Jade (FJ). This area of Par1 also contains the representation of the mystacial vibrissae. Neurons in this area of Par1 receiving projections derived from the vibrissae are arranged in discrete functional units ("barrels"), which are revealed by cytochrome oxidase (CO) histochemistry. Here, rats given mAMPH (four injections of 4 mg/kg, sc, 2-h intervals between injections) showed FJ-positive neurons in Par1 that were located predominantly near the perimeter of the CO-dense barrels. Thus, the Par1 neurons damaged by multiple administration of mAMPH are located within whisker barrels.
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PMID:Repeated administration of methamphetamine damages cells in the somatosensory cortex: overlap with cytochrome oxidase-rich barrels. 1084 49

This study investigated the organization of a vibrissal pathway that arises from the interpolar division of the spinal trigeminal complex (SP5i), transits through the ventral posterior medial nucleus (VPM), and innervates the somatosensory cortical areas in the rat. Using Fluoro-Gold and biotinylated dextran amine, respectively, as retrograde and anterograde tracers, the following organization plan was disclosed. The SP5i projection arises from a population of small-sized neurons that selectively innervate the ventral lateral part of VPM. In cytochrome oxidase-stained material, this region does not display any barreloid arrangement, but Fluoro-Gold injections in single barrel columns labeled rods of cells that extend caudally into the ventral lateral division of VPM. Thus, on the basis of retrograde labeling, barreloids were divided into core and tail compartments, which correspond to the rod segments running across the dorsal and ventral lateral parts of VPM, respectively. Double-labeling experiments revealed that SP5i afferents innervate the tail of barreloids. The anterograde labeling of thalamocortical axons show that most "core cells" project to a single barrel column, whereas some "tail cells" give rise to branching axons that innervate the second somatosensory area and the dysgranular zone of the barrel field. Injections that straddled the transition zone between the core and tail regions disclosed cells projecting to a single barrel column and to the surrounding dysgranular zone. These results suggest that the projection of "barreloids cells" to the granular and/or dysgranular zones relates to the class of prethalamic input(s) they receive.
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PMID:Parallel streams for the relay of vibrissal information through thalamic barreloids. 1100 5

We characterized the organization of corticostriatal projections from rodent primary somatosensory cortex (SI), testing the hypothesis that projections from SI areas representing subcomponents of the forelimb exhibit greater neostriatal overlap than projections from areas representing separate body parts. The anterograde tracers Fluoro-Ruby (FR), Alexa Fluor (AF), and biotinylated dextran amine (BDA) were injected into physiologically identified regions of rat SI. Injection locations were confirmed by examining the SI barrel fields and limb representations in tangential sections processed for cytochrome oxidase (CO). Experimental animals were divided into two groups: one group received multiple tracer injections in neighboring SI regions that represent separate body parts (whiskers, forepaw, and hindpaw); the other group received injections in SI areas that represent different components of the forelimb (forepaw, antebrachium, and brachium). The distribution of labeled terminals and their varicosities in the neostriatum and in the thalamus were plotted and quantitatively analyzed. For most animals, tracer overlap in the thalamus was either minimal or completely absent. In the neostriatum, projections from the whisker, forelimb, and hindlimb representations terminated in regions that rarely overlap with each other, while those originating from different parts of the forelimb representation were more likely to terminate in overlapping parts of the neostriatum. To the extent that neostriatal activation depends on corticostriatal convergence, the corticostriatal projections in the sensorimotor channel appeared to be organized so that neostriatal neurons may signal when multiple components of the same body part are activated simultaneously.
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PMID:Projections from primary somatosensory cortex to the neostriatum: the role of somatotopic continuity in corticostriatal convergence. 1261 38

The position of the caudal intralaminar nuclei within basal ganglia circuitry has largely been neglected in most studies dealing with basal ganglia function. During the past few years, there has been a growing body of evidence suggesting that the thalamic parafascicular nucleus in rodents (PF) exerts a multifaceted modulation of basal ganglia nuclei, at different levels. Our aim was to study the activity of the thalamostriatal pathway in rats with unilateral dopaminergic depletion. The experimental approach comprised first unilateral delivery of 6-OHDA in the medial forebrain bundle. Thirty days post-lesioning, animals showing a clear asymmetry were then subjected to bilateral injection of Fluoro-Gold (FG) within the striatum. Subsequently, expression of the mRNA encoding the vesicular glutamate transporter 2 (vGLUT2) was detected within thalamostriatal-projecting neurons (FG-labeled) by in situ hybridization and the results were confirmed by laser-guided capture microdissection microscopy followed by real-time PCR. The data showed that there was a marked neuronal loss restricted to PF neurons projecting to the dopamine-depleted striatum. Moreover, PF neurons innervating the dopamine-depleted striatum were intensely hyperactive. These neurons showed a marked increase on the expression of vGLUT2 mRNA as well as for the mRNA encoding the subunit I of cytochrome oxidase as compared with those neurons projecting to the striatum with normal dopamine content. Thus, the selective neurodegeneration of PF neurons innervating the striatum together with the increased activity of the thalamostriatal pathway coexist after nigrostriatal denervation.
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PMID:Consequences of unilateral nigrostriatal denervation on the thalamostriatal pathway in rats. 1663 57