摘要:

Abstract—A method has been developed for the isolation of a previously undescribed fibrous protein from rat brain. The newly isolated material consists of bundles of tightly packed 70‐80 Å diameter filaments. Based on studies employing degenerated rat optic nerve, it is proposed that these filaments correspond to the well‐described astrocyte filaments observed in sectioned preparations of mammalian brain. The purified filaments are stable over a wide temperature range, are not disrupted by colchicine, and exhibit limited solubility in the absence of denaturants or detergents. In neutral SDS‐polyacrylamide gel electrophoresis, the filament protein runs as a single band with an apparent molecular weight of 57,000 daltons. This preparation also migrates as a single band in alkaline urea gels, and as a well‐resolved doublet on discontinuous SDS‐urea gels. In all three electrophoretic systems, the filament subunits co‐migrate with rat brain tubulin. Comparative peptide maps of the filament subunits and tubulin indicate a large degree of homology. Our results suggest that microtubules and astrocyte filaments are composed of the same or very similar pr

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07594.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—Total nucleic acids of rat brain have been separated by agarose gel chromatography at 2m‐NaCl into DNA. transfer RNA plus low molecular weight RNA. and high molecular weight RNA fractions. The DNA fraction contained less than 1 per cent RNA by weight judged by either short‐term or long‐term labelling with ortho[32P]phosphate. The high molecular weight RNA fraction contained 28sand 18sribosomal RNAs and a heterogeneous population of 20‐60sRNAs, apparent after short‐term labelling and characterized by a high content of nearest‐neighbour‐labelled uridylic acid. The rapidly sedimenting (>30s) portion of these RNAs could be largely separated from ribosomal RNAs by gel filtration using 4% agarose. The ribosomal RNAs could be fully resolved into 28sand 18scomponents by agarose gel chromatography at 0.5m‐0.6m‐NaCl, as shown by analysis of their sedimentation and nuc

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07595.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—The hexafluoroisopropyl esters of trifluoroacetylated homovanillic acid (HVA) and 3‐hydroxy‐4‐methoxyphenylacetic acid (iso‐HVA) were the derivatives chosen for assay of these phenolic acids in lumbar cerebrospinal fluid (CSF) specimens from 65 control subjects. The mean value obtained in these specimens was 40.0 ± 23.5 ng/ml. Recovery of added HVA and iso‐HVA was 94 ± 2 per cent and reproducibility was ±5 per cent. CSF from Parkinson's disease patients undergoing treatment withl‐DOPA showed significant increases in HVA. Iso‐HVA was detected in those CSF samples obtained du

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07596.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—The NH2‐terminal amino acids of Wolfgram and Folch‐Lees proteolipids of bovine and human CNS myelin were determined using the cyanate method (Starke&Smyth, 1963) followed by direct amino acid analysis of the products. Glycine predominated in every case and was recovered in amounts similar to the results described by Whikehart&Lees(1973), who used a dansylation technique followed by thin layer chromatography of the DNS‐amino acids. In the present study substantial amounts of glutamic acid, serine, alanine and aspartic acid were also recovered, plus traces of other amino acids. Few differences were observed between Wolfgram and Folch‐Lees proteolipids. The end group products of purified W1 proteolipid of bovine Wolfgram fraction, of diazometholysed Folch‐Lees proteolipid, and of a sample of phosphatidyl serine had essentially the same composition. The similarity of these results, especially for both fractionated and unfractionated Wolfgram proteolipid, may be evidence that the observed products are derived from phosphoglycerides present in proteolipid rather than from the actual NH2‐terminals o

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07597.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—The effects of acute treatment with lithium ion (25 mm) on the levels of ATP, phosphocreatine and glucose were measured in anin vitropreparation of rat superior cervical ganglion. Similar analyses were performed on ganglia from rats fed a chronic lithium diet (0.5 mm). Ganglia were excised and de‐sheathed, then stimulated (5 Hz) or rested for 20, 40 or 80 min in normal or lithium‐containing Krebs‐Ringer bathing solutions. Following freeze drying, enzymatic pyridine nucleotide methods were used to measure fluorometrically ATP, phosphocreatine and glucose on portions of a ganglionic perchloric acid extract.After 20 min of incubation, normal ganglionic contents of ATP and phosphocreatine were higher than the initial zero time levels. Incubation for periods longer than 20 min resulted in ATP and phosphocreatine levels which were lower than those at zero time. Stimulation of normal ganglia caused a decrease in the contents of high‐energy phosphates relative to those in the resting state. Except for the 20 min time period the ATP levels were lower than normal in ganglia from rats chronically fed lithium. Levels of ATP and phosphocreatine in ganglia acutely exposed to lithium were significantly lower than in both normal ganglia and ganglia from chronically‐treated rats. In comparison to normal ganglia, significantly lower levels of glucose were found only for stimulated ganglia acutely exposed

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07598.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—The distribution of DBH activity between soluble and sedimentable fractions of hypotonic homogenates was examined in rat sympathetic ganglia and nerves after interruption of axonal transport. Local application of colchicine to superior cervical ganglia caused an increase mainly in particulate DBH activity, which was presumably bound to membranes. Likewise, in sciatic nerves, particulate DBH activity accumulated on both sides of a ligature and disappeared from a region well below a ligature much faster than did soluble activity. On the other hand, 18 h after simultaneous application of two ligatures to the nerve, neither total DBH activity nor subcellular distribution of this activity changed in the isolated nerve region. More detailed analysis showed that ligation affected the distribution of DBH activity within a fraction that sedimented at 140,000gafter homogenization of nerves in isotonic sucrose. Just above a ligature, osmotically releasable DBH activity was a smaller proportion of the sedimentable activity than in control nerves. However, as compared to controls, osmotically releasable DBH activity was a larger proportion of the activity in the sedimentable fraction from a region well below a ligature. A model was developed which accounts for some of these results by postulating that DBH is associated with different compartments in sciatic nerve which have different rates of transport and different proportions of soluble and bound enzym

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07599.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—A method was developed for perfusion of the spinal subarachnoid space in the rat. Bidirectional steady‐state fluxes of [14C]glycine between spinal fluid and plasma were measured. [14C]glycine clearance from spinal fluid was 5‐fold greater than its clearance from plasma. Glycine was transported out of spinal fluid by a saturable process, and the rate of transport was unaffected by the other depressant amino acids, GABA, β‐alanine, and taurine. Perfused [14C]glycine and [3H]GABA distributed in an intracellular compartment in spinal cord. The preparation should be useful for study of the release of these inhibitory amino acids from the intact spi

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07600.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—The accumulation, metabolism and stimulated‐induced release of 5‐HT in the nervous system of the snail was studied. When nervous tissue was incubated at 24°C in a medium containing [14C]5‐HT or [3H]tryptophan, tissue: medium ratios of about 25:1 and 4:1 respectively were obtained after 45 min incubation.The process responsible for [14C]5‐HT accumulation showed properties of an active transport system: it was temperature sensitive and was greatly inhibited by dinitrophenol and ouabain. Furthermore, the accumulation process was inhibited by imipramine and desipramine.Of a number of analogues of indole,N‐acetyl‐5‐HT and 5‐hydroxytryptophan were the most potent in the inhibition of the accumulation of [14C]5‐HT. The presence of a large molar excess of amino acids had little effect.A small amount (less than 14 per cent) of the accumulated [14C]5‐HT was metabolized to form 5‐hydroxyindole acetic acid, even after long periods (2 h) of incubation. The accumulated [3H]tryptophan was metabolized to form 5‐hydroxytryptophan and 5‐HT; the content of formed [3H]5‐HT increased with incubation time whilst the [3H]5‐hydroxytryptophan remained more or less constant.The presence ofp‐chlorophenylalanine in the incubation medium did not interfere with the accumulation of [3H]tryptophan, though it inhibited the formation of [3H]5‐hydroxytryptophan and to a greater extent [3H]5‐HT.A rapid efflux of the accumulated [14C]5‐HT from snail nervous tissue was observed on electrical stimulation. Slower release resulted when the Ca2+ion content of the incubation medium was replaced by Mg2+ions. There is also a slight efflux of radioactive substances following electrical stimulation in tissues previously incubated in [3H]tryptophan. Most of this radioactivity was attributed to the formed [3H]5‐HT.The data support the idea that 5‐HT is a transmitter‐substance in the snailHelix pomatia, and that re‐uptake of the substanc

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07601.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—In experiments designed to localize the increased turnover of phosphoprotein‐P which occurs in respiring brain slices as a result of electrical stimulation, a cell separation procedure was used to prepare a fraction enriched in neuronal cell bodies from incubated slices labelled with [32P]phosphate. Labelled phosphoprotein was found to be twice as concentrated in the neuron‐enriched fraction as in other fractions. Electrical stimulation for 10 s increased the rate of incorporation of [32P]phosphate into phosphoproteins in the neuron‐enriched fraction by 25 per cent (P<0.05), but had no effect on incorporation into a partially purified glial fraction contaminated with neuropil and cell

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07602.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract—Lipid composition has been determined in brain frontal lobe gray and white matter from a 5‐month‐old patient who died from Menkes' disease, and from a normal control patient of the same age.Total cholesterol and the amount of cholesterol esters were significantly increased in the case of Menkes' disease, whereas the values for free cholesterol were nearly unchanged.In white matter a decrease in total galactolipids was observed in the pathological brain.The values for total phospholipids were unchanged for the tissues, but the ratio between phosphatidylcholines and phosphatidylethanolamines (including ethanolamineplasmalogens) in white matter from the patient seemed increased. The fatty acid pattern of phosphatidylethanolamines (including ethanolamineplasmalogens), phosphatidylcholines and sphingomyelin were similar to those of the normal control. Phosphatidylethanolamines from pathological tissues contained 25–30 per cent polyunsaturated fatty acids with four, five or six doubl

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1974.tb07603.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY