bluuebunny/crossref_metadata_2025 huggingface dataset:
GANGLIOSIDES IN NERVOUS TISSUE CULTURES AND BINDING OF 125I‐LABELLED TETANUS TOXIN, A NEURONAL MARKER
Authors: Dimpfel W. , Huang R. T. C. , Habermann E.
Published: October 2006

Abstract— —Continuous cell lines, primary cell cultures derived from embryonic CNS, and homogenates made from adult and embryonic CNS were compared with respect to their lipid pattern and their ability to bind 125I‐labelled tetanus toxin. In parallel experiments de novo synthesis of gangliosides in the cell lines was studied, using [14C]glucosamine as precursor. Of the total lipid only gangliosides were specifically labelled by [14C]glucosamine. The patterns of the de novo synthesized gangliosides corresponded to those present in the respective cells.

Pronounced binding of 125I‐labelled toxin was only detectable in tissues containing long‐chain gangliosides (ganglioside C which represents GDIb and GTI).

Accordingly, hybrid (neuroblastoma x glioma) cells, due to their lack of long‐chain gangliosides, bound just‐discernible amounts of labelled toxin. When previously exposed to gangliosides, their binding of tetanus toxin tremendously increased.

It was concluded that only the long‐chain gangliosides in the neuronal cells are functionally involved in the binding of the tetanus toxin and that these acceptors of tetanus toxin can be transplanted.
SUBCELLULAR DISTRIBUTION OF A HEAT‐STABLE PROTEIN INHIBITOR OF CYCLIC AMP‐DEPENDENT PROTEIN KINASE IN RAT BRAIN
Authors: Roskoski R. , Frederick C. E.
Published: October 2006

Abstract— Cyclic AMP (cAMP)‐dependent protein kinase catalyzes the phosphorylation of polypeptidic serine and threonine residues according to the following chemical equation: ATP + protein → phospho‐protein + ADP. A heat stable, trypsin labile factor present in brain, skeletal muscle and other tissues inhibits enzymatic phosphorylation of some proteins and enhances that of others. Since brain is one of the richest sources of adenylate cyclase, cAMP, cAMP‐dependent protein kinase and the heat stable protein kinase inhibitor and because they may play a role in neurotransmission, an investigation of the subcellular distribution of the heat stable factor in rat brain was undertaken. Although present in the nuclear, mitochondrial and microsomal fractions, the highest activity of protein kinase inhibitor is in the soluble fraction: its activity parallels that of the cytoplasmic enzyme marker, lactate dehydro‐genase. The inhibitory activity is also found in the synaptosome or pinched‐off nerve ending fraction. Following osmotic lysis of this fraction, about 90% of the factor occurs in the soluble fraction. On the other hand, only 40% of the cAMP‐dependent protein kinase is solubilized and 60% remains membrane‐bound. Using this membrane‐bound protein kinase, phosphorylation of endogenous substrate is unaltered by inhibitor, but phosphorylation of added histone substrate is decreased.
ACETYLCHOLINESTERASE IN MOUSE BRAIN, ERYTHROCYTES AND MUSCLE
Authors: Adamson Eileen D.
Published: October 2006

Abstract— The properties of the enzyme acetylcholinesterase (EC 3.1.1.7) from mouse brain, erythrocytes and muscle were investigated. The enzymes were examined by gel filtration in Sephadex G‐200, polyac‐rylamide gel electrophoresis, immunological reactions, active‐site labelling with tritiated di‐isopropyl‐phosphorofluoridate and also their kinetic properties were compared. All three enzymes appeared to have a single active small mol. wt. component of 80,000 to 82,000 which produced higher mol. wt. forms by aggregation. The partial purification of the enzyme from brain was achieved by affinity chromatography and this product was used to prepare antibodies. The purified immunoglobulin was shown to react with all three enzymes.
ELECTROPHORUS ELECTRICUS ACETYLCHOLINESTERASES; SEPARATION AND SELECTIVE MODIFICATION BY COLLAGENASE1,2
Authors: Johnson C. D. , Smith Susan P. , Russell R. L.
Published: October 2006

Abstract— The multiple forms of acetylcholinesterase found in the electric organ of the eel Electrophorus electricus have been fractionated by differential solubilization from an ammonium sulfate precipitate by means of a column elution procedure (King, 1972). This procedure cleanly separates ‘native’ forms from ‘degraded’ forms, and subsequent sedimentation reveals three native and two degraded forms. All three native forms, in distinction to the degraded ones, are insoluble at low ionic strength and are shifted to higher sedimentation constants by limited collagenase treatment. These results suggest that the long (500 Á) tail seen previously on the native forms of this enzyme (Dudaiet al., 1973; Riegeret al., 1973a, b) may contain collagen.
PARTIAL PURIFICATION AND CHARACTERIZATION OF SORBITOL DEHYDROGENASE FROM RAT BRAIN1
Authors: Rehg J. E. , Torack R. M.
Published: October 2006

Abstract— Sorbitol dehydrogenase (EC 1.1.1.14) was isolated and purified 700‐fold from rat brain. Most substrate specificities and properties are similar to those reported for sorbitol dehydrogenase from other mammalian tissues; however, the substrate specificity of this brain enzyme does not conform to the d‐cis 2,4 dihydroxy configuration. The physiological substrate for sorbitol dehydrogenase is probably sorbitol. The isolation of sorbitol dehydrogenase from rat brain tissue is confirmation that (1) all the constituents of the sorbitol (polyol) pathway are present in the brain and that (2) fructose synthesis from glucose in this tissue proceeds via the intermediate formation of sorbitol.
CARRIER MEDIATED GLUCOSE TRANSPORT IN CAPILLARIES ISOLATED FROM RAT BRAIN1
Authors: Goldstein G. W. , Csjtey Judit , Diamond I.
Published: October 2006

Abstract— Uptake of 2‐deoxy‐d‐glucose (2‐DG) was investigated in capillaries isolated from rat brain. A high affinity, carrier‐mediated transport system was defined with an apparent Km for 2‐DG of 93 μM. Uptake was temperature‐dependent and markedly inhibited by phloretin and selected hexose isomers. The apparent Ki for d‐glucose inhibition of 2‐DG uptake was 98 μM. Essentially all of the 2‐DG retained by the capillary preparation could be released by sonication and 95% was recovered as free unphosphorylated 2‐DG. Uptake was not sodium‐dependent and not altered by insulin. These results suggest that movement of glucose across the blood‐brain barrier through endothelial cells probably is not rate‐limiting unless blood glucose levels are extremely low.
EFFECTS OF PRE‐ OR POSTNATAL DEXAMETHASONE, ADRENOCORTICOTROPHIC HORMONE AND ENVIRONMENTAL STRESS ON PHENYLETHANOLAMINE N‐METHYLTRANSFERASE ACTIVITY AND CATECHOLAMINES IN SYMPATHETIC GANGLIA OF NEONATAL RATS
Authors: Gianutsos G. , Moore K. E.
Published: October 2006

Abstract— Injections of dexamethasone (0.1 mg/kg/day, s.c.) on the first 2–3 days of life increased the phenylethanolamine‐N‐methyltransferase (PNMT) activity and epinephrine content of the superior cervical ganglion (SCG) and stellate ganglion of neonatal rats; the dopamine content was unaltered while norepinephrine was slightly reduced in these ganglia. Dexamethasone did not alter the PNMT activity or epinephrine content of the salivary glands or heart. The PNMT activity and epinephrine content of the SCG remained elevated for 10–14 days. Pretreatment with 6‐hydroxydopamine did not alter the dexamethasone effects.

Injections of adrenocorticotrophic hormone (ACTH) (25 munits/rat twice a day) or exposure to a cold stress (4°C, 3 times a day) on the first 2–3 days of life, elevated the plasma concentration of corticosterone, and also increased the PNMT activity and epinephrine content in SCG of neonatal rats. Injecting pregnant rats with dexamethasone or ACTH, or exposing them to cold or restraint stress on the last 3 days of gestation increased the PNMT activity and epinephrine content in the SCG of their pups. These results indicate that the actions of dexamethasone on neonatal sympathetic ganglia may be mimicked by increasing the plasma concentration of endogenous adrenocortical steroids.
LIGHT‐INDUCED REDUCTION IN CYCLIC GMP OF RETINAL PHOTORECEPTOR CELLS IN VIVO: ABNORMALITIES IN THE DEGENERATIVE DISEASES OF RCS RATS AND rd MICE1
Authors: Farber Debora B. , Lolley R. N.
Published: October 2006

Abstract— The effect of light on the content of cyclic GMP in degenerative retinae of Royal College of Surgeons (RCS) rats and rd mice was compared with that in control retinae during postnatal maturation. In vivo, the cyclic GMP content of retinae of control rats or mice is light‐dependent after photoreceptor outer segments develop. Mature retinae of control animals have high levels of cyclic GMP in the dark which are reduced 40–50% upon illumination. In the rd mouse disorder, a light‐induced reduction in cyclic GMP content is observed while the rod outer segments are morphologically intact. The rd photoreceptor cells possess a phosphodiesterase which, when stabilized by freeze‐drying, has a Km similar to that of control photoreceptors, and an apparent Vmax that is below normal. It is suggested that developing rd visual cells have an abnormality in cyclic GMP metabolism which results in the accumulation of cyclic GMP within the entire cell but which does not prevent the light‐mediated reduction of cyclic GMP in their outer segment organelles. In the RCS dystrophy, a light‐induced reduction in cyclic GMP content is observed also during the period when photoreceptor outer segments are present. The cyclic GMP content of dark‐ or light‐adapted RCS retinae is below that of the respective controls. Biochemical and morphological observations show that cyclic GMP levels increase in rd visual cells and that they are reduced in photoreceptor cells of RCS retina before the onset of visual cell degeneration. Until detailed knowledge of the role of cyclic GMP in the visual cells is known, it is suggested that high or low levels of cyclic GMP in rd and RCS photoreceptors, respectively, result from differences in the etiology or histopathology of the mouse and rat diseases.
STIMULATED INCORPORATION OF AMINO ACIDS INTO PROTEINS OF SYNAPTOSOMAL FRACTIONS INDUCED BY DEPOLARIZING TREATMENTS
Authors: Wedege E. , Luqmani Y. , Bradford H. F.
Published: October 2006

Abstract— Rat cortical synaptosome preparations incorporated l‐amino acids into protein at a linear rate over 30–60 min. Synaptosomes showed large increases in incorporation after treatment with electrical pulses, veratrine or K+. This was inhibited (controls, 73%; electrically stimulated 58%) by cycloheximide and by chloramphenicol (28 and 44% respectively). Omission of Ca2+ from the medium had no effect, but the absence of Na+ greatly diminished the stimulus‐induced increase in incorporation due to pulses. Electrical pulses, veratrine and K+ (in order of effectiveness), all showed their greatest proportional effects on amino acid incorporation into the Triton‐X‐100 insoluble portions of the synaptosomal membrane: the ‘junctional complex’, soluble in SDS, and the residue. Tetrodotoxin (1 μm), although ineffective when potassium was the stimulus, prevented or reduced the respiratory response, K+ loss and differential amino acid release, as well as the amino acid incorporation into protein observed with pulses and veratrine.

C‐6 glioma cells showed no stimulus‐dependent increase in incorporation. Preliminary data, of gel electrophoretic analysis, on the proteins labelled under our conditions is presented.
ADENOSINE UPTAKE BY CHOLINERGIC SYNAPTOSOMES FROM TORPEDO ELECTRIC ORGAN
Authors: Meunier F. M. , Morel N.
Published: October 2006

Pure cholinergic synaptosomes prepared from the electric organ of Torpedo are able to take adenosine up efficiently and convert it to ATP. The apparent Km of the adenosine uptake is 2.4 μM and the Vm: 518 pmol/30′/mg prot. The uptake system exhibits a high specificity towards adenosine, as shown by the lack of competition with analogues. Tubercidin blocks the uptake competitively and dipyridamole is a very potent non competitive inhibitor (Ki= 4 × 10‐8 M).

Considering that during nerve activity ATP is released extracellularly and can modulate transmitter release, the physiological significance of adenosine uptake is discussed as a possible mechanism to terminate the ATP action.
RELATIONSHIP BETWEEN SYNAPTOSOMAL UPTAKE AND RELEASE OF [14C]GABA, [14C]DIAMINOBUTYRIC ACID AND [14C]β‐ALANINE1
Authors: Redburn Dianna A.
Published: October 2006

[14C]GABA is taken up by rat brain synaptosomes via a high affinity, Na+‐dependent process. Subsequent addition of depolarizing levels of potassium (56.2 MM) or veratridine (100 μM) stimulates the release of synaptosomal [14C]GABA by a process which is sensitive to the external concentration of divalent cations such as Ca2+, Mg2+, and Mn2+. However, the relatively smaller amount of [14C]GABA taken up by synaptosomes in the absence of Na+ is not released from synaptosomes by Ca2+ ‐dependent, K +‐stimulation.

[14C]DABA, a competitive inhibitor of synaptosomal uptake of GABA (Iversen & Johnson, 1971) is also taken up by synaptosomal fractions via a Na + ‐dependent process; and is subsequently released by Ca2+ ‐dependent, K+‐stimulation. On the other hand, [14C]β‐alanine, a purported blocker of glial uptake systems for GABA (Schon & Kelly, 1974) is a poor competitor of GABA uptake into synaptosomes. Comparatively small amounts of [14C] β‐alanine are taken up by synaptosomes and no significant amount is released by Ca2+ ‐dependent, K+‐stimulation.

These data suggest that entry of [14C]GABA into a releasable pool requires external Na+ ions and maximal evoked release of [14C]GABA from the synaptosomal pool requires external Ca2+ ions. The GABA analogue, DABA, is apparently successful in entering the same or similar synaptosomal pool. The GABA analogue, β‐alanine, is not.

None of the compounds or conditions studied were found to simultaneously affect both uptake and release processes. Compounds which stimulated release (veratridine) or inhibited release (magnesium) were found to have minimal effect on synaptosomal uptake. Likewise compounds (DABA) or conditions (Na+‐free medium) which inhibited uptake, had little effect on release.
REGULATION OF CYCLIC NUCLEOTIDE PHOSPHODIESTERASES OF CEREBRAL CORTEX BY Ca2+ AND CYCLIC GMP
Authors: Filburn Charles R. , Colpo Frank , Sacktor Bertram
Published: October 2006

Abstract—

Cyclic nucleotide phosphodiesterase activity of porcine cerebral cortical extracts was measured with 0.1–100 μM‐cyclic AMP and cyclic GMP and found to be dependent on both Ca2+ and added cyclic nucleotides. With decreasing substrate concentration activity with cyclic GMP became more dependent on Ca2+ whereas hydrolysis of cyclic AMP became less dependent. Cyclic GMP at 3 μM stimulated the hydrolysis of 0.1–10μM‐cyclic AMP in the absence of Ca2+ (< 10‐10M) but inhibited activity with 200 μM‐Ca2+ present. This differential, substrate‐ and Ca2+‐dependent regulation was attributed to the presence of at least two types of phosphodiesterase distinguishable by DEAE‐column chromatography. In the absence of Ca2+, activity with 1 μM‐cyclic GMP eluted in one minor peak followed by two major peaks, D‐I and D‐II. Activity with 1 μM‐cyclic AMP eluted almost entirely in D‐II. Hydrolysis of cyclic AMP in D‐II was activated by cyclic GMP. With added Ca2+ plus a Ca2+‐dependent regulator (CDR), activity with 1 μM‐cyclic GMP was markedly increased and eluted entirely at D‐I. Total activity with 1 μM‐cyclic AMP was only moderately increased and eluted as D‐I with a shoulder at D‐II. Elution profiles with 100 μM‐substrate were relatively independent of substrate, with D‐I predominant with Ca2+·CDR present and D‐II predominant in its absence. Kinetic analysis of rechromatographed D‐I showed a 20‐ to 40‐fold activation by Ca2+·CDR that was largely due to an increase in Vmax, with only 50% decreases in Km Both substrates competitively inhibited hydrolysis of the other with Ki values equal to their respective Km values (1.7 μM for cyclic GMP and 48 μM for cyclic AMP with Ca2+‐CDR present). Studies with theophylline and trifluoperazine indicate differential, substrate‐dependent inhibitions of both enzymes. These findings demonstrate that phosphodiesterase activity in neural tissue is subject to regulation by Ca2+, cyclic GMP, and inhibitors in a complex, substrate‐specific and concentration‐dependent manner.
COLD RESISTANCE OF THE BRAIN DURING HIBERNATION: THE ROLE OF STEARYL CoA DESATURASE IN BRAIN AND LIVER AS THE SOURCE FOR MONOENES
Authors: Goldman Stephen S.
Published: October 2006

Abstract—

Brain and liver stearyl CoA desaturase activity and its associated microsomal electron transport chain was investigated in both the warm‐adapted and hibernating hamster.

It was shown that the activity of this enzyme in brain was essentially the same in both the warm‐adapted and hibernating hamster. In liver an 8‐fold increase in desaturase activity was observed for the hibernator without corresponding increases in the activity of the microsomal electron transport chain.

It is concluded that the increase of monoenes in brain that contributes to the lipid adaptation probably results from peripheral production of these fatty acids.
INDUCTION AND PROPERTIES OF PYRUVATE KINASE OF THE CEREBRAL HEMISPHERE OF RATS OF VARIOUS AGES1
Authors: Chainy G. B. N. , Kanungo M. S.
Published: October 2006

Abstract—

The induction of pyruvate kinase (ATP: pyruvate 2‐O phosphotransferase, EC 2.7.1.40; PK) by estradiol or testosterone in the cerebral hemisphere of male and female rats of different ages was studied. There is a marked decrease in the activity of the enzyme of normal male and female rats with increasing age. Orchiectomy decreases its activity in young and old rats, but not in adult rats. Ovariectomy decreases its activity significantly in all the ages. Estradiol (50μg/100g body wt.) induces its activity in castrated male and female rats, but its effect is greater in female rats. A higher dose of estradiol (100μg/100g body wt.) has age‐ and sex‐dependent induction. Testosterone (50 and 100μg/100g body wt.) has very little effect on its activity in castrated male and female rats of the three ages. The Km values for PEP and ADP, and the Kt values for ATP and l‐phenylalanine for the partially purified enzyme of the cerebral hemisphere of normal young and old rats are the same. Preincubation of the enzyme with l‐alanine reverses the l‐phenylalanine induced inhibition. The concentration of l‐alanine required for this effect is the same for both ages. The concentration of Mg2+ required to reverse the inhibitory effect of ATP is the same for young and old rats. Estradiol and testosterone added directly to the incubation mixture do not have any effect on the enzyme activity. These data suggest that the nature of the enzyme molecule does not change with age, but that its induction properties change with age.
EVIDENCE FOR THE HETEROGENEITY OF L‐2,4‐DIAMINOBUTYRIC ACID UPTAKE IN RAT CORTEX
Authors: Kennedy A. J. , Neal M. J.
Published: October 2006

Abstract—

The uptake of L‐[3H]DABA by rat cerebral cortex slices was studied. Analysis of the kinetic data obtained provides evidence that DABA entry is mediated by both high and low affinity carriers. When cortical slices were incubated in the presence of equimolar [3H]DABA and [14C]GABA the ratio of entry of the two radionuclides was found to depend upon the loading concentration. The specificity of the uptake of 1 μM and 1 mM‐L‐DABA was examined: GABA and DABA were relatively potent inhibitors of 1 μM‐DABA uptake whereas an equal concentration of histidine did not produce significant inhibition. In contrast, DABA and histidine were markedly more potent as inhibitors of 1 mM‐DABA uptake than was GABA. It is concluded from these experiments that L‐DABA is transported into cortical slices by a carrier which has high affinities for both DABA and GABA and by a second lower affinity carrier which prefers DABA as a substrate to GABA. On the basis of a comparison of the effects of inhibitors on [3H]DABA and [3H]GABA uptake it is estimated that approx 26% of DABA uptake at 1 μM does not occur by the high affinity carrier whereas at 1 mM‐DABA this proportion rises to 62–67%.
LOCALIZATION OF THE THY‐1 ANTIGEN IN RAT BRAIN AND SPINAL CORD BY IMMUNOFLUORESCENCE
Authors: Barclay A. N. , Hydén H.
Published: October 2006

Abstract— The Thy‐1 antigen of rat brain is a membrane glycoprotein of molecular weight 17,500. It was localized in sections of brain and spinal cord by indirect immunofluorescence using rabbit antisera raised against purified Thy‐1 and fluorescein conjugated purified sheep F(ab')2, anti‐(rabbit IgG) antibody fragments. The specificity of the anti‐(Thy‐1) sera was tested by a quantitative indirect radioactive binding assay which is particularly useful for ascertaining the specificity of reagents used in immunohistochemical studies. Purified Thy‐1 was used to absorb the anti‐(Thy‐1) sera for controls in the immunofluorescence experiments. Strong specific fluorescence was found throughout the gray matter of brain and spinal cord with lesser amounts in white matter. The nuclei of all neural cells and also myelin lacked fluorescence. Some of the large neurons contained weak cytoplasmic fluorescence, but the majority of the immunofluorescence was located in the neuropil of the brain and spinal cord. There was an indication that Thy‐1 was associated with synaptic knobs due to its presence in synaptic glomeruli and its granular appearance around some neurons. An additional association with glial membranes could not be excluded.
CORRECTION FACTORS FOR ‘BINDING’ STUDIES; MODEL SYSTEMS FOR GABA BINDING TO A SYNAPTOSOMAL–MITOCHONDRIAL FRACTION OF RAT CEREBRAL CORTEX1
Authors: Somoza E. , DeFeudis F. V.
Published: October 2006

Abstract—

Correction methods currently used in ‘binding’ experiments have been compared and a new approach is proposed. These methods have been applied to data on the ‘binding’ of GABA to a ‘synaptosomal‐mitochondrial’ fraction of rat cerebral cortex under various conditions. Results indicated that values for ‘corrected binding’ can differ greatly, depending upon the method employed. Calculations based on data obtained when using a high concentration of unlabelled GABA to displace ‘specific’ binding of [3H]GABA (‘cold ligand method’) under‐estimated the binding, because this method neglects the existence of a biochemically‐inert space which exists within the pellet even at 0°C and which traps labelled ligand. The other correction method, in which an inert labelled substance (e.g. sucrose) is used to measure the portion of the pellet occupied by trapped supernatant fluid (‘sucrose space method’), is more accurate, but does not take into account the amount of ligand that may be non‐specifically bound to the particulate portion of the pellet. The error with this method is small for ‘high‐affinity’ ligand‐receptor systems, but may be quite large for lower affinity systems. A method which takes into consideration both the inert space of the pellet and ligand that is non‐specifically bound to the pellet (‘fully corrected method’) is proposed. The three correction methods have been applied to a study of the kinetic parameters of GABA binding to a ‘synaptosomal‐mitochondrial’ fraction of rat cerebral cortex in the presence and absence of the GABA inhibitor, bicuculline‐methiodide. In some cases, the results showed qualitative as well as large quantitative differences, depending on the correction method employed.
INFLUENCES OF COLCHICINE, VINBLASTINE AND CYTOCHALASIN ON THE RELEASE OF 5‐HYDROXYTRYPTAMINE FROM RAT BRAIN SYNAPTOSOMES
Authors: Segawa T. , Murakami H. , Inouye A. , Tanaka Y.
Published: October 2006

Abstract—

Rat brain synaptosomes preincubated with [3H]5‐HT. were further incubated and the release of [3H]5‐HT from the preparation was studied. The spontaneous release consisted of an initial rapid phase followed by slower release. Incubation with 60 mM‐KCl increased the release while 60 mw‐NaCl did not affect it. The effect of KG was abolished when NaCl was omitted from the medium. The potassium‐induced release was Ca2+ ‐dependent while that induced by tyramine (10−5‐10−4M) and the spontaneous release did not depend on Ca2+. Vinblastine (10−5–2.5 X 10−4 M) caused an increase in the spontaneous release and an decrease in the potassium‐induced release, while it completely inhibited the release by tyramine at 2.5 X 10−4 M. Colchicine (5 X 10−5–10−3M) and cytochalasin D (10−5, 10−4 M) failed to produce any change in the release. Cytochalasin B (10−5, 10−4M) increased the spontaneous release and decreased the potassium‐induced release but it did not affect the release by tyramine. Colchicine (10−3 M). vinblastine (10−4 M) and cytochalasin B (10−4 M) did not affect significantly Na+.K+‐. Mg2‐ and Ca2+ ‐ATPase activities. These results suggest that none of microtubules. microfilaments and contractile protein participates in the mechanism of [3H]5‐HT release from synaptosomes, in vitro.
THE NATURE OF THE TWO PROTEINS OF BRAIN SPECIFIC ANTIGEN 14‐3‐2
Authors: Bock Elisabeth , Fletcher Lynne , Rider C. C. , Taylor C. B.
Published: October 2006

Abstract—

The three isoenzymes of rat brain enolase (2‐phospho d‐glycerate hydrolase EC 4.2.1.11.) χχ, χγ and γγ were separated by ion‐exchange chromatography and were tested for reaction with an antiserum against brain specific antigen 14‐3‐2. This monospecific antiserum affects the enolase activity of only the χγ and γγ isoenzymes.

Immunoelectrophoretic experiments show that the two proteins which react as 14‐3‐2 both contain γ enolase subunits, and one of these also contains χ enolase subunits.

It is concluded that the 14‐3‐2 antigen and the γ enolase subunit are identical, and that the two proteins which react immunologically as 14‐3‐2 are the χγ and γγ enolase isoenzymes.
PYRIDOXAL‐5′‐PHOSPHATE AS A COFACTOR FOR RAT BRAIN HISTIDINE DECARBOXYLASE1
Authors: Palacios J. M. , Mengod G. , Grad, F. P)Catoste M. , Blanco I.
Published: October 2006

Abstract—

The cofactor requirements of brain histidine decarboxylase activity have been studied. Preincubation with carbonyl reagents caused inhibition of the activity ranging from 90% for 10−2m‐semicarbazide, 10−3m‐phenylhydrazide and 10−3m‐hydroxylamine to 50% for isonicotinic acid hydrazide. Sodium borohydride, a reducing agent, also caused complete inhibition of activity. The histidine decarboxylase activity was maximal at 10−4m‐pyridoxal‐P concentration and was inhibited at higher concentrations of the cofactor.

The cofactor‐apoenzyme mode of binding was studied by dialysing brain homogenates against several media. Neither the dialysis against buffers alone nor against buffers containing semicarbazide nor cysteine plus EDTA caused a total loss of activity. A 50% of the activity dialysed easily while the other 50% remained ‘tightly’ bound to the apoenzyme. The dialysable and non dialysable activity is evenly distributed between the soluble and particulate activity.
β‐CARBOLINES: A TOOL FOR INVESTIGATING STRUCTURE‐ACTIVITY RELATIONSHIPS OF THE HIGH‐AFFINITY UPTAKE OF SEROTONIN, NORADRENALINE, DOPAMINE, GABA AND CHOLINE INTO A SYNAPTOSOME‐RICH FRACTION OF VARIOUS REGIONS FROM RAT BRAIN1
Authors: Rommelspacher H. , Strauss S. M. , Rehse K.
Published: October 2006

Abstract— Tetrahydronorharmane (tryptoline), the condensation product of tryptamine and formaldehyde, inhibits the high‐affinity uptake of serotonin and to a smaller extent that of noradrenaline into a synaptosome‐rich fraction from the hippocampus and hypothalamus respectively of rats. The uptake mechanisms of dopaminergic neurones of the hypothalamus, cholinergic neurones of the hippocampus, and GABA‐ergic neurones of the cerebral cortex are affected to a much lesser degree. Substitution of tetrahydronorharmane by fluor‐, chlor‐, methyl‐, hydroxy‐, methoxy‐, and catechol‐groups alters the inhibition. Drugs with substituents which attract electrons are relatively good inhibitors of the uptake of serotonin. The indole‐ring contributes to the binding of the molecule probably by forming a charge transfer complex with the uptake molecule. Pyrido (3,4‐b)‐indoles (harmala alkaloids) are weak inhibitors of the serotonin‐uptake compared with respective piperidoindoles (tetrahydro‐β‐carbolines).

The potency of the drugs to inhibit uptake is different for each uptake system. The order among the drugs with respect to their affinity for the uptake site varies, too.
γ‐GLUTAMYLHISTAMINE: A MAJOR PRODUCT OF HISTAMINE METABOLISM IN GANGLIA OF THE MARINE MOLLUSK, APLYSIA CALIFORNICA
Authors: Weinreich Daniel
Published: October 2006

Abstract—

The metabolism of histamine in the nervous system of Aplysia, was studied by incubating ganglia for various time periods in a medium containing radiolabelled histamine. After 4 h of incubation, >89% of the 3MH‐ or 14C‐label measured in the ganglion extract was converted to a single radioactive product whose electrophoretic and chromatographic mobilities were identical with γ‐glutamylhistamine. No evidence was found to indicate that radiolabelled histamine could be deaminated, N‐methylated, N‐acetylated, or oxidized in this nervous system. Acid hydrolysis of radioactive material prepared from ganglia incubated in either 14C‐histamine alone or in combination with 14C‐glutamate resulted in the liberation of labelled histamine and/or labelled glutamate. These results indicate that γ‐glutamyl‐ation of histamine may be an important physiological mechanism for histamine catabolism in molluscan nervous tissue.
EFFECT OF PHOSPHATIDYLSERINE ON ACETYLCHOLINE OUTPUT FROM THE CEREBRAL CORTEX OF THE RAT
Authors: Casamenti F. , Mantovani P. , Amaducci L. , Pepeu G.
Published: October 2006

Abstract—

The effect of sonicated suspensions of phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine injected intravenously on acetylcholine release from the cerebral cortex was investigated in urethane anaesthetized rats. The electroeorticogram was also recorded.

Phosphatidylserine caused a dose dependent, calcium dependent increase in acetylcholine output with no electrocorticografic changes. The increase, 75% peak effect after 150 mg/kg, was abolished by septal lesions and pretreatment with pimozide. Phosphatidylserine had no effect on acetylcholine release from brain slices in vitro.

Phosphatidylethanolamine was approximately half as active as phosphatidylserine and phosphatidylcholine had no effect on acetylcholine output in vivo.

It is concluded that phosphatidylserine exerts an indirect stimulating action on a septio‐cortical cholinergic pathway.
SUBCELLULAR LOCALIZATION OF PROTEIN CARBOXYL‐METHYLASE AND ITS SUBSTRATES IN RAT PITUITARY LOBES
Authors: Gagnon Claude , Axelrod Julius
Published: October 2006

Abstract—

Subcellular distribution of protein carboxyl‐methylase (PCM) and its endogenous substrates the methyl acceptor proteins (MAP) have been studied in the anterior, the posterior and the intermediate lobes of the rat pituitary gland. In all three lobes, PCM was found to be a cytosolic enzyme whereas the highest MAP specific capacity was observed in the lysate of the granular fractions. The methylated proteins from the lysates of the granular fractions and the cytosolic fractions were analyzed with a novel electrophoretic system which prevents the hydrolysis of the protein‐methyl esters. Gel electrophoretic profiles from the lysates of the granular fractions were different from those of the cytosolic fractions. In the lysatcs of the granular fractions. the MAP had a molecular weight of less than 25,000 suggesting that the methylated polypeptides in these fractions were the pituitary peptide hormones (and their subunits) and neurophysins.
LIPID‐MEDIATED GLYCOSYLATION OF A WHITE MATTER MEMBRANE GLYCOPROTEIN WITH AN APPARENT MOLECULAR WEIGHT OF 24,0001
Authors: B. Harford Joe , J. Waechter Charles
Published: October 2006

White matter membrane preparations from pig brain catalyze the transfer of [14C]mannose from exogenous [14C]mannosylphosphoryldolichol into an endogenous oligosaccharide lipid. Under the same incubation conditions label is also incorporated into endogenous membrane glycoproteins. The enzymatic labeling of both classes of endogenous acceptors is stimulated by the addition of Ca2+. Several enzymatic properties of the mannosyltransferase activity responsible for the transfer of mannose from mannosylphosphoryldolichol into the oligosaccharide lipid intermediate have been examined. The [Man‐14C] oligosaccharide lipid synthesized by this in vitro system has the solubility, hydrolytic and chromatographic characteristics of a pyrophosphate‐linked oligosaccharide derivative of dolichol. The free [Man‐14C]oligosaccharide liberated from the carrier lipid by mild acid treatment is estimated to contain 8 glycose units. All of the [14C]mannosyl units in the [Man‐14C]oligosaccharide derived from exogenous [14C]mannosylphosphoryldolichol are released as free [14C]mannose by an α‐mannosi‐dase. No [14C]mannose is released during incubation with a β‐mannosidase. The presence of an N,N′‐diacetylchitobiose unit at the reducing end of the lipid‐bound [Man‐14C]oligosaccharide is indicated by its susceptibility to digestion by endo‐β‐N‐acetylglucosaminidase H.

Pronase digestion of the enzymatically labeled [Man‐14C]glycoprotein yields a single [Man‐14C]gly‐copeptide fraction on Bio‐Gel P‐6 that appears to be slightly larger than the free [Man‐14C]oligosac‐charide released from the carrier lipid by mild acid hydrolysis. The [Man‐14C]glycopeptide is cleaved by endo‐β‐N‐acetylglucosaminidase H, and the neutral [Man‐14C]oligosaccharide product appears to be identical to the product formed when the lipid‐bound [Man‐14C]oligosaccharide is degraded by the endoglycosidase. The glycopeptide linkage in the [Man‐14C]glycoprotein is stable to mild alkali treatment. These results are consistent with the dolichol‐linked [Man‐14C]oligosaccharide, mannosy‐lated via exogenous [14C]mannosylphosphoryldoiichol, being subsequently transferred en bloc from dolichyl pyrophosphate to asparagine residues in endogenous membrane polypeptide acceptors. SDS‐polyacrylamide gel electrophoresis of the [Man‐14C]glycoprotein, labeled when white matter membranes are incubated with [14C]mannosylphosphoryldolichol. revealed a major labeled polypeptide with an apparent mol wt of 24,000. A minor labeled membrane glycoprotein is also seen, having an apparent mol wt of 105,000.
DIVALENT CATION SPECIFICITY OF THE CALCIUM REQUIREMENT FOR FAST TRANSPORT OF PROTEINS IN AXONS OF DESHEATHED NERVES
Authors: Lavoie P.‐A. , Bolen F. , Hammerschlag R.
Published: October 2006

The presence of a requirement for calcium during the fast transport of [3H]protein in axons was assessed in desheathed spinal nerves of bullfrog. The nerves were desheathed locally along 4 mm of their length, and desheathing was judged effective on the basis of an enhanced uptake of [3H]leucine into that region of nerve trunk. Desheathing per se had a slight inhibitory effect on transport. Incubation of desheathed nerve trunks in calcium‐free medium reduced transport by 60‐80% relative to that in desheathed nerves incubated in normal medium. Addition of Mg2+ or Sr2+ to the calcium‐free medium allowed transport to proceed normally. Addition of Co2+ or Mn2+ to normal medium did not affect transport in desheathed isolated nerve trunks. When ganglia and nerve trunks were both incubated in medium containing 0.18 mM‐CoCl2, transport was depressed to a similar extent proximal and distal to the desheathed region. This again indicates that Co2+ does not inhibit transport in desheathed nerves, whereas it does inhibit transport in the ganglia. Additive inhibitory effects were observed when ganglia were incubated in medium containing 0.018 mM‐CoCl2, and desheathed nerves were incubated in calcium‐free medium. Differences in the divalent cation specificities of the axonal and ganglionic calcium requirements suggest that calcium supports transport in nerves in a manner distinct from its role in maintaining transport in spinal ganglia. It is concluded that the ganglionic calcium requirement involves initiation of axonal transport in the soma rather than translocation in the intraganglionic region of axon.
[3H]HARMALINE AS A SPECIFIC LIGAND OF MAO A–II. MEASUREMENT OF THE TURNOVER RATES OF MAO A DURING ONTOGENESIS IN THE RAT BRAIN
Authors: Nelson D. L. , Herbet A. , Glowinski J. , Hamon M.
Published: October 2006

The combined measurement of MAO A activity (using [3H]5‐HT as a specific substrate) and [3H]harmaline binding capacity indicated that the concentration of MAO A in brain was higher in 14‐28 day old rats than in adult animals. The turnover rates of this enzyme in the forebrain and the brain stem of young (14‐28 day old) and adult rats were calculated by following the recovery of MAO A activity and of [3H]harmaline binding capacity after an acute treatment with pargyline (75mg/kg i.p.). Both the fractional rate constant for MAO A degradation and its synthesis rate per g of fresh tissue were significantly higher in young animals. However, the calculation of the absolute synthesis rates of MAO A per brain area gave very similar values in young and adult animals: 1.3‐1.5 × 1013 molecules of MAO A synthesized per day in the forebrain and 2.3‐2.9 × 1012 molecules per day in the brain stern.

The results illustrate the validity of using [3H]harmaline binding to evaluate possible changes in the turnover rate of MAO A in tissues.
RELEASE OF [3H]GABA FROM IN VITRO PREPARATIONS: COMPARISON OF THE EFFECT OF DABA AND β‐ALANINE ON THE K+ AND PROTOVERATRINE STIMULATED RELEASE OF [3H]GABA FROM BRAIN SLICES AND SYNAPTOSOMES1
Authors: Hammerstad J. P. , Cawthon M. L. , Lytle C. R.
Published: October 2006

It has been proposed that the major portion of [3H]GABA released from rat cortical slices upon exposure to high K+ comes from a neuronal pool. Using carrier mediated exchange diffusion of DABA or β‐alanine in the superfusion medium for GABA in the slice as a technique for manipulating neuronal and glial pools of GABA, it was found that DABA but not β‐alanine substantially reduced the K+ stimulated release of [3H]GABA. The present study using synaptosomes as an in vitro model of the nerve ending was undertaken to ascertain whether this neuronal pool of releasable [3H]GABA was associated with a specific transmitter pool in nerve endings. A continuous superfusion system employing a Ca2+ pulse to produce a calcium coupled release (Levyet al, 1973) was used to study the effect of two concentrations (20 μm, 1 mm) of DABA and β‐alanine on the release of [3H]GABA from synaptosomes. In contrast to the results in slices, DABA at both concentrations had no effect on the release of [3H]GABA from synaptosomes in spite of evidence that exchange diffusion was occurring. With protoveratrine as the releasing agent there was no effect of DABA on the release of [3H]GABA from either slices or synaptosomes. The results suggest that the major portion of [3H]GABA released from cortical slices by high K+ comes from a non‐transmitter pool in the neuron. Use of K+ stimulated release of amino acids from cortical slices as a criterion for neurotransmitter function must be viewed with caution.
THE GAUCHER MOUSE: ADDITIONAL BIOCHEMICAL ALTERATIONS
Authors: Stephens M. C. , Bernatsky A. , Legler G. , Kanfer J. N.
Published: October 2006

Abstract— Additional biochemical alterations were observed in the Gaucher mouse. The activity of β‐xylosidase in brain, spleen and liver was considerably decreased in this animal model and acid phosphatase in plasma was increased about 4‐fold. The levels of the splenic hexosylceramides, glucosyl‐ceramide, lactosylceramide, trihexosylceramide, globoside and hematoside were all increased in comparison with controls. Brain ganglioside content was examined and very few differences were noted; however, there was a tendency towards slight elevations for the monosialogangliosides and GD1a and lower values for GD1b and GT.
FROG SCIATIC NERVE MYELIN: A CHEMICAL CHARACTERIZATION
Authors: Smith Marion Edmonds , Curtis Benson M.
Published: October 2006

Abstract— The lipid and protein compositions of PNS myelin from two species of frogs, Xenopus laevis and Rana catesbiana, are compared with each other and with those of the rat. The relative proportions of PNS myelin lipids in the two frog species and rat are very similar except for a somewhat higher phosphatidyl choline content in frog myelin. The protein compositions of frog PNS myelin of the two species are also much alike, but a protein smaller than P2 is found in Xenopus, which is not seen in Rana. The results are discussed in terms of results found by others in other species and the compositions are compared with those of the corresponding CNS myelin.
NEUROCHEMICAL PARAMETERS IN THE HYPERRESPONSIVE PHASE AFTER A SINGLE DOSE OF NEUROLEPTICS TO MICE
Authors: Hyttel John
Published: October 2006

Abstract— Four days after a single dose of teflutixol (5 mg/kg i.p.), at which time mice are superresponsive to dopamine agonists, e.g. apomorphine, the specific binding of [3H]haloperidol, [3H]cis (Z)‐flupenthixol, [3H]apomorphine, [3H]dopamine, [3H]propylbenzilylcholine mustard and [3H]GABA to striatal membranes in vitro is equal to that of saline‐treated mice. Specific binding of [3H]haloperidol is also unchanged 3 days following a single dose of fluphenazine (5mg/kg i.p.) and 2 days following haloperidol (5 mg/kg i.p.), but slightly decreased 3 days following cis(Z)‐flupenthixol (5 mg/kg i.p.).

The possibility that remaining neuroleptic or active metabolites could obscure a slight increase in dopamine receptor binding was rejected, since remaining amounts of [3H]teflutixol in the final binding assay 4 days after intraperitoneal injection of [3H]teflutixol (5 mg/kg) were too small to influence the binding of [3H]haloperidol in vitro.

It is concluded that the pharmacological superresponsiveness and the decrease in dopamine synthesis and release seen after the initial receptor blockade following a single dose of neuroleptic drugs in mice are nor accompanied by changes in dopamine, muscarine or GABAergic receptor characteristics in corpus striatum. The possibility that changes occur in a small number of functional operative dopamine receptors cannot be excluded, however.
DEVELOPMENT OF ACETYLCHOLINESTERASE MULTIPLE MOLECULAR FORMS IN CHICKEN MUSCLES
Authors: Bajgar J. , Pařízek J. , Procházková O.
Published: October 2006

Abstract— AChE activity and protein content in chicken ALD and PLD muscles was studied during pre‐ and postnatal development. Protein content in both muscles increased whereas AChE activity increased in ALD and decreased in PLD during development. All studied values reached the steady‐state 3 weeks after hatching.

Electrophoretic separation of the samples showed three molecular forms of AChE present in both adult ALD and PLD muscles. Two molecular forms in ALD muscle increased slowly, one form quickly. On the other hand, the activity of AChE forms in PLD muscle decreased with different rates. It appears from these results that the multiple molecular forms of AChE in muscles are not of the same physiological importance.
DECREASED AXONAL FLUX OF RETROGRADELY TRANSPORTED GLYCOPROTEINS IN EARLY EXPERIMENTAL DIABETES
Authors: Jakobsen J. , Sidenius P.
Published: October 2006

Abstract— Anterograde and retrograde flux of axonal transported glycoproteins were examined in streptozotocin diabetic rats with 4 weeks’duration of the metabolic derangement.

[3H]Fucose and [14C]NeuNAc were injected into the fifth lumbar root ganglion and the accumulation of TCA‐PTA insoluble activity proximal and distal to a sciatic nerve ligature was measured.

Accumulation of glycoproteins during 2 h collection periods was decreased distal to a ligature in diabetic animals whereas no abnormality of proximal accumulation was observed. These findings demonstrate an abnormality of the retrograde transport of glycoproteins in early experimental diabetes.
SUPPLEMENTATION OF A WHEAT BREAD DIET WITH LYSINE AND THREONINE: EFFECTS UPON INTRAUTERINE GROWTH AND BRAIN BIOCHEMISTRY
Authors: Chase H. Peter , Crnic Linda S.
Published: October 2006

Abstract— During pregnancy, rats were fed either a standard chow diet, a wheat bread diet or a wheat bread diet supplemented with lysine and threonine. At birth, the offspring of the dams fed the supplemented diet differed from the chow fed animals only in having a smaller amount of protein in the combined cerebellum and brain stem area while the pups whose dams were fed the bread diet showed lower brain weights, deficits in protein in all brain parts and deficits in DNA in the cerebrum.
ULTRASTRUCTURAL AND BIOCHEMICAL COMPARISONS OF DENDRODENDRITIC SYNAPTOSOMES FROM BOVINE SUPERIOR COLLICULI AND OLFACTORY BULBS WITH AXODENDRITIC AND AXOSOMATIC SYNAPTOSOMES
Authors: Kornguth Steven E. , Scott Grayson , Jaramillo Rocio
Published: October 2006

Abstract– The buoyant density, ultrastructure and protein composition of dendrodendritic (DD), axodendritic (AD) and axosomatic (AS) synaptosomes were compared. DD synaptosomes prepared from either bovine superior colliculi or olfactory bulbs sedimented in 0.32 m‐sucrose at 1000 g whereas AD and AS synaptosomes from frontal and temporal lobe cortices sedimented at 10.000 g. In gradients of Renografin the DD contacts banded at a density of 1.12 whereas AD and AS banded at 1.07. The DD contacts appeared as large clusters of serial contacts, and each individual terminal had a mean surface area of 1.48 μm2; the mean area of AD and AS terminals was less than 0.35 μm2. The protein compositions of DD, AD and AS synaptosomes were quite similar, with minor exceptions. These findings suggest that different synaptosmal types evolved from common membrane constituents.
FLUORESCENCE SPECTROSCOPY ON HUNTINGTON'S FIBROBLASTS
Authors: Pettegrew Jay W. , Nichols John S. , Stewart R. Malcolm
Published: October 2006

Abstract– 8‐Anilino‐1‐naphthalene sulfonic acid (ANS), a fluorescent probe specific for membrane polar‐apolar interfaces, has been used to investigate differences in corrected excitation, emission and scanned excitation polarization spectra of intact age, sex and passage number matched Huntington's disease (HD) and normal fibroblasts grown in cell culture. At passage number 4, the HD fibroblasts, compared to normals, exhibited a 30‐fold increase in excitation and emission intensity, a 30 nm blue shift of the emission maximum and a 0.18 polarization unit increase. These findings suggest that the ANS molecule experiences either increased binding sites or an increased quantum yield, a more nonpolar environment, and a more restricted motion in HD fibroblasts. Continued subculture at higher passages (10) showed a change of these findings towards normals. These fluorescent studies support the concept that a membrane abnormality is present in HD.