bluuebunny/crossref_metadata_2025_split huggingface dataset:
ISOLATION AND PURIFICATION OF A VERATRIDINE BINDING PROTEOGLYCOLIPID FROM RAT GASTROCNEMIUS TISSUE1
Authors: Taylor Richard F. 
Published: October 2006

AbstractA lipoidal‐protein complex has been isolated from rat gastrocnemius tissue which exhibits a highly specific binding capacity for [3H]veratridine. Purification of the complex has been accomplished by a number of chromatographic steps including affinity chromatography in organic solvents utilizing a resin synthesized by oxirane coupling of veratridine to Sephadex LH‐20. The purified complex binds veratridine but not tetrodotoxin or a number of cholinergic ligands. Veratridine binding to the complex is inhibited by aconitine but not tetrodotoxin or cholinergic ligands. The complex has both veratridine saturable (KD= 13 μm) and non‐saturable (KD1 Mm) binding components. Preliminary chemical analysis showed that the complex is a proteoglycolipid with a protein: carbohydrate: phosphorous ratio of 1.5:1.1:1.0. A discussion is presented favoring the identity of the isolated proteoglycoiipid as a portion of the macromolecular complex comprising the axonal sodium action potential ionophore.
THE IN VITRO FORMATION OF ACETYL‐ASPARTYL‐PEPTIDO‐SEROTONIN COMPLEXES BY PIG HYPOTHALAMIC TISSUE EXTRACTS
Authors: Edminson P. D. 
Published: October 2006

Abstract—Peptido‐serotonin complexes are formed on incubation of pig hypothalamic tissue extracts with acetyl‐aspartate, the amino acids glu. ser, gly and ala. an ATP‐regenerating system and serotonin. The purification and partial characterisation of two acetyl‐aspartyl‐peptido‐serotonin complexes is described.
REVERSAL OF AXONAL TRANSPORT IN REGENERATING NERVES1
Authors: Bulger V. T. , Bisby M. A. 
Published: October 2006

Abstract— Orthograde and retrograde axonal transport were studied in rat sciatic nerves which had been crushed and either allowed to regenerate, or prevented from doing so by tightly ligaturing the nerve. At various intervals after crushing the nerve. L‐[3H]leucine was injected into the lumbosacral spinal cord. and the subsequent transport of labeled protein in motoneuron axons was quantitated by measuring the accumulation of labeled protein at collection crushes made proximal to the original nerve crush.Accumulations proximal to the collection crushes (orthograde transport) 9‐11 h after injection (p.i.). decreased within I day of nerve injury, but returned to normal values as regeneration proceeded. In non‐regenerating nerves accumulations remained depressed for at least 30 days.Accumulations distal to the collection crushes (retrograde transport) 9‐11 h pi. increased over the first 5 days following injury but returned to normal values as regeneration proceeded. In non‐regenerating nerves accumulations remained elevated. The time‐course of retrograde transport of newly‐synthesized protein also returned to normal during nerve regeneration.It is suggested that changes in retrograde transport during regeneration may inform the neuron cell body of the progress of regeneration and elicit appropriate metabolic responses. among which may be the changes in orthograde transport that follow axotomy.
HIGH AFFINITY l‐[3H]GLUTAMATE BINDING TO POSTSYNAPTIC RECEPTOR SITES ON RAT CEREBELLAR MEMBRANES
Authors: Foster A. C. , Roberts P. J. 
Published: October 2006

Abstract— l[3H]glutamate binding was investigated in membrane preparations derived from rat cerebellum, an area of the brain where it is likely that a high density of postsynaptic glutamate receptors occurs. Glutamate was hound specifically and, in freshly prepared membranes, was optimal under physiological conditions of pH and temperature and was associated with the synaptic membrane fraction of the cell. Specific binding occurred through a single, high‐affinity process with a KD, of 744 nM and a capacity of 73 pmol/mg protein. Unlike the findings reported for GABA, the specific binding of glutamate to fresh membranes did not involve an uptake site. Comparison of the potencies of a wide range of compounds with known pharmacological activities, demonstrated that their ability to displace specific glutamate binding was consistent with specific interactions with glutamate receptors.
INCREASE IN LARGE NEUTRAL AMINO ACID TRANSPORT INTO BRAIN BY INSULIN
Authors: De Montis M. G. , Olianas M. C. , Haber B. , Tagliamonte A. 
Published: October 2006

Abstract—The administration of oral glucose to fasted rats produced a decline of all large neutral amino acid levels in serum, including that of the free fraction of tryptophan. In addition to this well known effect, it also decreased the brain concentrations of leucine, isoleucine and valine, while increasing those of tryptophan, tyrosine and phenylalanine. The total concentration of large neutral amino acids in serum was decreased by 44%, while it was slightly increased in brain. Analogous results were obtained in 4 rats injected with exogenous insulin. Moreover, the administration of either glucagon or isoproterenol to rats force‐fed with glucose produced a decline in total serum tryptophan concentration proportional to that of the rise in FFA, while it increased free serum tryptophan and brain tryptophan levels. It can be concluded that insulin stimulates the transport of large neutral amino acids from blood to brain and that the level of free serum tryptophan also controls the entry of tryptophan into the brain under the influence of insulin.
CHARACTERISTICS AND REGIONAL DISTRIBUTIONS OF TWO DISTINCT [3H]NALOXONE BINDING SITES IN THE RAT BRAIN
Authors: Squires R. F. , Braestrup C. 
Published: October 2006

Abstract—Using [3H]naloxone at a concentration of 4.5 nm, the potent opiate agonist etorphine as well as the potent antagonist diprenorphine displace only about 75% of specific naloxone binding P2 fractions from rat whole forebrain, without additive effect. Several other opiates and antagonists completely displace specific naloxone binding. This indicates that etorphine and diprenorphine specifically bind to one and the same naloxone binding site (type I) while leaving another naloxone binding site (type II) unaffected. Type I binding sites are much more thermo‐labile than type II. [3H]Naloxone binding to type I sites is unaffected by incubation temperature in the range 10 to 25°C. while binding type II sites decreases rapidly with increasing incubation temperature, no specific type II binding being detectable at or above 20°C. The two naloxone receptor types also differ with respect to pH dependence, and affinity for naloxone with types I and II having affinity constants (Kd) of 2 and 16 nm, respectively, at 0°C. The two binding sites have different regional distributions with high relative levels of type II receptors in cerebellum and low relative levels in pons‐medulla and striatum. In whole rat brain there are about 4 times as many type II receptors as type I. These results suggest that naloxone and several other opiate agonists and antagonists bind to two distinct receptor types which are probably not agonist/antagonist aspects of the same receptor.
EFFECTS OF SYMPATHECTOMY ON AXOPLASMIC TRANSPORT OF SELECTED ENZYMES INCLUDING MAO AND OTHER MITOCHONDRIAL ENZYMES
Authors: Schmidt Robert E. , Ross C. David , McDougal David B. 
Published: October 2006

Abstract— Axoplasmic transport in guanethidine sympathectomized and control rats was investigated by monitoring the accumulations of various enzyme activities proximal to a ligature placed on the sciatic nerve. Sympathectomy affected the accumulations of three different mitochondrial enzymes quite differently: the accumulation of monoamine oxidase (MAO, EC 1.4.3.4) activity was inhibited 65% or more, that of hexokinase (HK, EC 2.7.1.1) activity was only inhibited 26%, while accumulation of glutamic dehydrogenase (GDH, EC 1.4.1.3) activity was unaffected by Sympathectomy. Accumulation of AChE (EC 3.1.1.7) activity was depressed 40%, but accumulations of the activities of the lysosomal enzyme, acid phosphatase (acid P'tase, EC 3.1.3.2), and of the cytosolic enzyme, choline acetyltransferase (CAT, EC 2.3.1.6) were unchanged.Despite impressive inhibition of MAO accumulation, the intrinsic activity of this enzyme in sciatic nerve was unaffected by Sympathectomy. The existence in nerve of isozymes of MAO was demonstrated using the inhibitors clorgyline and deprenyl. Transported MAO activity was almost entirely type A; intrinsic activity was 2/3 type A and 1/3 type B.The differential response of the accumulations of the three mitochondrial enzyme activities measured was interpreted to indicate the existence, within neurons, of mitochondria with different enzyme complements.
SOLUBILIZATION OF TRYPTOPHAN‐5‐MONOOXYGENASE FROM THE PINEAL GLANDS AND EXISTENCE OF AN ACTIVATING SUBSTANCE IN THE TISSUE EXTRACT1
Authors: Hori Shinichiro , Ohotani Sachiko 
Published: October 2006

Abstract—A particle bound tryptophan‐5‐monooxygenase in bovine pineal glands was solubilized by a combination of high pH (PH 8.5), high salt concentration (0.5 M‐KCl or NaCl), and sonication (20 kHz, 200 W, 30min), We recovered 75% or more of the monooxygenase activity of the tissue homogenate in the 105,000 g supernatant thus confirming our previous study (Horiet al., 1976). The solubilized enzyme preparation contained an activating substance which was also particle bound and which activated the monooxygenase when preincubated together with the enzyme and dithiothreitol.The solubilized tryptophan‐5‐monooxygenase was purified about 6‐fold over the tissue homogenate using ammonium sulphate fractionation and column chromatography on hydroxylapatite and Sephacryl S‐200. The activating substance was separated from the monooxygenase during hydroxylapatite column chromatography. The activating substance was shown to be different from phospholipids, such as L‐α‐lysophosphatidyl choline and L‐α‐phosphatidyl‐L‐serine, and from heparin or bovine serum albumin, although bovine serum albumin significantly activated the monooxygenase. Further experiments have suggested that both the monooxygenase and the activating substance are modified by dithiothreitol and that these modified materials interact to give the active form of the monooxygenase.
ACYL AND ALK‐1′‐ENYL GROUP COMPOSITION OF ETHANOLAMINE PHOSPHOGLYCERIDES OF HUMAN BRAIN
Authors: Pullarkat Raju K. , Reha Henry 
Published: October 2006

Abstract—Ethanolamine phosphogylcerides (EPG) of human brain gray and white matter were analyzed for their alk‐1′‐enyl group and fatty acid compositions in sn‐glycerol positions 1 and 2. Gray matter contained more 18:0 (54%) and less 18:1 (24.5%) alk‐1′‐enyl residues than white matter (16% and 57%. Sixty per cent of alk‐1′‐enyl 18.1 in gray matter was the (n‐7), against 71%, in white matter. Both gray and white matter contained small amounts of 18:1 (n‐5) and (n‐3) isomers.The fatty acids in position I of the phosphatidylethanolamines were more saturated than the corresponding alk‐1′‐enyl groups of the plasmalogens. The ratios of monoenoic fatty acid isomers in position 1 were markedly different from those of the corresponding alk‐1′‐enyl groups in gray matter. The fatty acid patterns in position 2 of plasmalogen and phosphatidylethanolamines of white matter were similar except for 22:4(n‐6) which was concentrated in the plasmalogen (16% against 10%, in the phosphatidyl ethanolamine). In gray matter, the same trend was noted.The data suggest that alk‐1′‐enyl residues and the fatty acids in position 1 as well as the fatty acids in position 2 of alk‐1′‐enyl acyl and diacyl type EPG in both gray and white matter are, at least in part, of different provenance.
METABOLISM OF MALONIC ACID IN RAT BRAIN AFTER INTRACEREBRAL INJECTION
Authors: Koeppen Arnulf H. , Mitzen Edward J. , Papandrea John D. 
Published: October 2006

Abstract—Labeled malonic acid ([1‐14C] and [2‐14C]) was injected into the left cerebral hemisphere of anesthetized adult rats in order to determine the metabolic fate of this dicarboxylic acid in central nervous tissue. The animals were allowed to survive for 2, 5, 10. 15 or 30min. Blood was sampled from the torcular during the experimental period and labeled metabolites were extracted from the brain after intracardiac perfusion.There was a very rapid efflux of unreacted malonate in the cerebral venous blood. Labeled CO2 was recovered from the venous blood and the respired air after the injection of [1‐14C]malonate but not after [2‐14C]malonate. The tissue extracts prepared from the brain showed only minimal labeling of fatty acids and sterols. Much higher radioactivity was present in glutamate, glutamine, aspartate, and GABA. The relative specific activities (RSA) of glutamine never rose above 1.00. Aspartate was labeled very rapidly and revealed evidence of 14CO2 fixation in addition to labeling through the Krebs cycle. GABA revealed higher RSA after [1‐14C]malonate than after [2‐14C]malonate. Sequential degradations of glutamate and aspartate proved that labeling of these amino acids occurred from [1‐14C] acetyl‐CoA and [2‐14C] acetyl‐CoA, respectively, via the Krebs cycle. Malonate activation and malonyl‐CoA decarboxylation in vivo were similar to experiments with isolated mitochondria. However, labeled malonate was not incorporated into the amino acids of free mitochondria. The results were compared to data obtained after intracerebral injection of [1‐14C]acetate and [2‐14C]acetate.
ON THE ORIGIN OF VANILLYLMANDELIC ACID AND 3‐METHOXY‐4‐HYDROXY‐PHENYLGLYCOL IN THE RAT BRAIN
Authors: Adér J.‐P. , Muskiet F. A. J. , Jeuring H. J. , Korf J. 
Published: October 2006

Abstract— The effects of electrothermic destruction and electrical stimulation of the locus coeruleus on the brain levels of vanillylmandelic acid (VMA), 3‐methoxy‐4‐hydroxyphenylglycol (MOPEG) and noradrenaline (NA) were studied in the rat. Fourteen days after destruction of the locus coeruleus, the content of NA in the hippocampus and that of MOPEG in the rest of the brain were decreased by more than 70% and 50% respectively.Stimulation of the locus coeruleus induced a decrease in hippocampal levels of NA of 38%, while MOPEG levels were found to be increased more than 3‐fold After intraventricular injection of 1 μg of adrenaline (A), the levels of MOPEG were Substantially increased In none of these experiments was any variation in VMA levels found, These results suggest that in the rat brain endogenous VMA is not a metabolite of either NA or A The formation of MOPEG from A as well as from NA appears to be possible.
STIMULATORY EFFECTS OF SUBSTANCE P ON NEURITE EXTENSION AND CYCLIC AMP LEVELS IN CULTURED NEUROBLASTOMA CELLS
Authors: Narumi Shigehiko , Maki Yoshitaka 
Published: October 2006

Abstract— Synthetic substance P initially increased cyclic AMP levels and subsequently induced neurite extension in cultured neuroblastoma N 18 cells. The magnitude of these effects depended on the concentration of fetal calf serum (FCS) in the culture medium, being more evident in the presence of a lower (0.1%) concentration of FCS.In Eagle's medium containing 0.1% FCS, low concentrations of substance P (10−7‐10−5 M) increased cyclic AMP levels and stimulated neurite extension.In Eagle's medium containing 5%FCS, both substance P at concentrations of 10−5‐10−3M and dibutyryl cyclic AMP at concentrations of 10−4‐10−2M increased cyclic AMP levels and stimulated neurite extension. The activities of acetylcholinesterase, (Na++ K+)‐, HCO3− and Mg2+ ‐stimulated‐ATPase were also increased. Cell growth was inhibited.Substance P at concentrations of 10‐7‐10−5M also stimulated the adenylate cyclase activity of a particulate fraction of N 18 in a concentration‐dependent manner.
DEVELOPMENT OF (Na+‐K+)‐ATPase IN RAT HINDBRAIN: INCREMENTS IN PARALLEL WITH Na+‐DEPENDENT PHOSPHORYLATION AND K+‐pNITROPHENYLPHOSPHATASE1
Authors: Bertoni John M. , Siegel George J. 
Published: October 2006

Abstract—Rat hindbrain NaI‐enriched microsomal (Na+‐K+)‐ATPase activity, K+‐pNPPase activity, and Na+‐dependent steady‐state phosphorylation levels all increase approx 10‐fold relative to microsomal protein between 5 days prenatally and 60 days postnatally. These activities, as well as the mean wet weight of the hindbrain, are at half of their 60 day values shortly after the 10th postnatal day. For all ages, these hindbrain activities average over twice those found in the forebrain in a companion paper (Bertoni & Siegel, 1978). Increases during development in the amount of the related phosphorylatable polypeptide, estimated by densitometry of stained polyacrylamide gels containing fixed amounts of microsomal protein dissolved in SDS, are in agreement with increases in steady state levels of Na+‐dependent phosphorylation. The fraction of total phosphorylation that is Na+‐dependent rises steadily during development consistent with, but not obligatorily due to, a conversion of some of the previously Na+‐independent portion. Mg2+‐ATPase and Mg2+ ‐pNPPase activities and steady‐state Na+,‐independent phosphorylation levels do not increase in parallel during development. These observations add further support to the proposed partial reaction scheme for (Na+‐ K+)‐ATPase. The major increments in (Na +‐K+)‐ATPase occur simultaneously with the deposition of specialized plasma membranes, particularly in the molecular layer of the cerebellum, as described in previous studies of rat hind brain.
HISTAMINE AND MAST CELLS IN DEVELOPING RAT BRAIN
Authors: FERRER I. , PICATOSTE F. , Rodergas E. , Garcia A. , Sabria J. , BLANCO I. 
Published: October 2006

Abstract—The number and distribution of mast cells in rat brain were determined at different postnatal ages. The number of brain mast cells was found to change during ontogenic development following the same pattern as brain histamine (HA) levels. The calculated HA content of brain mast cells was close to the HA content of the crude nuclear fraction at every age studied. Since most of the brain HA in the newborn sediments with the crude nuclear fraction, these results suggest that the developmental pattern of brain HA reflects changes in the number of brain mast cells, that is, in the size of the mast cell HA pool. The HA content of the supernatant of the crude nuclear fraction corrected for mast cell HA contamination, on the other hand, follows a developmental pattern similar to that of other known neurotransmitters.
QUAKING MOUSE MYELIN: BIOCHEMICAL CHARACTERIZATION OF ZONAL GRADIENT SUBFRACTIONS
Authors: Waehneldt T. V. , Fagg G. E. , Matthieu J.‐M. , Baumann N. A. , Neuhoff V. 
Published: October 2006

AbstractThe brains of Quaking and littermate control mice were fractionated by differential and density gradient centrifugation into soluble, microsomal, myelin and related (SN 4) fractions. There were no apparent differences in protein composition between any Quaking and control fraction with the exception of myelin and SN 4. Analysis of CNP activity indicated that in Quaking animals a high proportion of the total activity was localized in microsomal fractions, while in controls a large percentage of activity was found in myelin and SN4; in contrast, there were no marhcd differences in the distribution of AChE activity between Quaking and control fractions.The yield of myelin isolated from Quaking animals was 3.6%, of that from controls by electron microscopy myelin fractions from both Quaking and controls consisted of compact myelin whorls. Zonal centrifugation on continuous sucrose gradients demonstrated that both control and Quaking myelin was distributed in a bell‐shaped mode with peak densities at 0.66 0.68 and 0.71‐0.75 M‐sucrose, respectively. The specific activity of CNP was generally lower in mutant subfractions than in controls. Protein analysis revealed that there were similar qualitative trends between light and heay myelin subfractions from both mutant and control animals, although the levels of proteolipid and small basic proteins were substantially lower in all Quaking fractions. These results indicate that. although all mutant myelin subfractions are compositionally abnormal, the type of particle heterogeneity in Quaking myelin is similar to that observed in controls.
VULNERABILITY OF THE IMMATURE RAT BRAIN TO PHENYLACETATE INTOXICATION: POSTNATAL DEVELOPMENT OF THE DETOXICATION MECHANISM
Authors: Loo Y. H. , Fulton T. , Miller K. A. , Wisniewski H. M. 
Published: October 2006

AbstractPhenylacetate is not excreted to any significant extent as the free acid in rat urine, but must be metabolized in the liver and kidney, first to phenylacetyl‐CoA, then to phenylacetylglycine. One hour after [14C]phenylacetate loading, the radioactivity in the liver and kidneys of the young rat could all be accounted for as unchanged phenylacetate (50‐5573, phenylacetylglycine (35–40%), and phenylacetyl‐CoA (5–8%). In the brain, the radioactivity was present mainly as phenylacetate (82–90%); only 10–18% was found as phenylacetyl‐CoA. The formation of phenylacetyl‐CoA appeared to be the rate limiting step in the clearance of phenylacetate.In the urine at least 95% of the radioactivity was present as phenylacetylglycine, less than 1% as phenylacetate, and 3–4% as phenylacetyl‐CoA. The concentration of phenylacetylglycine in the urine was therefore used as a measure of the in vivo rate of phenylacetatc clearance. This detoxication process was found to develop postnatally. The formation of phenylacetylglycine was barely detecrabie in the newborn rat and remained relatively slow for about 2 weeks. During the third week a large increase in enzymatic activity, approx 40% occurred. Adult level of activity was reached in the 40 day old rat.The extremely slow rate of detoxication in the newborn animal was reflected in the persistence of high concentrations of phenylacetate in the tissues. The relevance of our findings to human phenyl‐ketonuria is discussed
THE TURNOVER AND SUBCELLULAR LOCALIZATION OF THE CHICK FOREBRAIN SMALL NUCLEAR RNAs
Authors: Gunning P. W. , Austin L. , Jeffrey P. L. 
Published: October 2006

AbstractAnalysis of 2 day old chick forebrain RNA on polyacrylamide gels revealed the presence of the 29S, 18S, 5.5s and 5s rRNAs, 4S tRNA and the small mol wt nuclear RNA (snRNA) species K, L, C, DD and G. The turnover of these molecules was studied following the intracerebral injection of [3H]uridine into 2 day old animals. The specific activities of these molecules declined over a 23 day time course and all displayed first‐order decay kinetics. Apparent half‐lives (in days) for 29S (7). 18S (S), L (24), C (6.5), DD′ (8.5), 5.5S (7), 5S (13), G (6) and 4S (7) were obtained.The subcellular localization of the snRNAs was studied in 5 day old chick forebrain. The snRNAs accounted for almost 17% of nuclear RNA, in contrast to their low levels in whole forebrain (1.2%). This was due to an approx 20‐fold nuclear enrichment of C, DD′, G′ and H. Relatively low levels of K and L were present within the nuclear fraction. However, K and L, and to a lesser extent C and DD, were readily detected within the post‐microsomal supernatant. Production of a pH 5 enzyme fraction from this supernatant resulted in a 2‐3‐fold enrichment of K, L, C and DD′ with respect to tRNA. The polysome containing fractions also displayed significant levels of L with about 1 mol of L per 30 of 5S rRNA.A new method for the determination of the subcellular distribution of the snRNAs is described. It depends upon the purity of the nuclear, microsomal and cell sap subfractions rather than upon total recoveries from such fractions.Utilizing the relative amounts of these RNA species within whole forebrain and the major subfractions, distributions (as a percentage within each fraction) were obtained. The observation of significant levels of K, L, C and DD within the cytoplasmic fractions raises some doubts about previous suggestions of an exclusively nuclear role for these molecules. It is proposed that the snRNAs may be involved in a multistage interaction within the process of eukaryotic gene expression.