bluuebunny/crossref_metadata_2025 huggingface dataset:
THE SUBCELLULAR DISTRIBUTION AND NUCLEOTIDE SPECIFICITIES OF Na+, K+‐STIMULATED ADENOSINE TRIPHOSPHATASE AND [14C]ADENOSINE DIPHOSPHATE‐ADENOSINE TRIPHOSPHATE EXCHANGE REACTIONS IN RAT BRAIN
Authors: Stahl W. L.
Published: October 2006

Abstract—

(1) The subcellular distributions of Na‐K ATPase and [14C]ADP‐ATP exchange activities were studied in rat brain. The data presented are not consistent with a discrete localization of these enzymes in any given fraction, but nerve endings and microsomes had similar specific activities. The supernatant fraction had the highest exchange and the lowest Na‐K ATPase activities, measured at a concentration of 3 mm‐MgCl2.

(2) Nucleotide specificity of the Na‐K ATPase was determined in all fractions, and this enzyme system showed an absolute requirement for ATP. The [14C]ADP‐ATP exchange, measured at 3mm‐MgCl2, possessed broader specificity and also was active toward ITP, UTP and GTP; this serves to differentiate it from the Na‐K ATPase.

(3) Treatment of nerve ending fractions with NaI medium removed the bulk of the [14C]ADP‐ATP exchange activity without loss in Na‐K ATPase activity.

(4) The exchange activity in NaI‐insoluble fractions was insensitive to NaCl in the presence of 3 mm‐MgCl2, but it was stimulated 502‐820 percent at low MgCl2 concentrations, a finding which may be consistent with the postulated role of this exchange reaction in the Na‐K ATPase system.
FACTORS INFLUENCING RESPIRATORY CONTROL IN BRAIN MITOCHONDRIA
Authors: Higgins E. S.
Published: October 2006

Abstract—

A simple technique was described for isolation of the mitochondrial fraction from central nervous tissue of the rat. The fraction so prepared satisfied structural and functional criteria of intactness and relative homogeneity. Oxidation of various substrates and the influences of inhibitors and experimental conditions were examined. The refractoriness of brain mitochondria to thyroxine was confirmed. Oxidation of glutamate was characterized by a very high degree of respiratory control. There was a pronounced Mg requirement by mitochondria in the aerobic active state, but not in the controlled state. Reverse acceptor control was manifest during succinate oxidation by Mg deficient mitochondria.
THE APPEARANCE OF GANGLIOSIDE DURING EMBRYOLOGICAL DEVELOPMENT OF THE FROG1
Authors: Yiamouyiannis J. A. , Dain J. A.
Published: October 2006

Abstract—

Embryological stages after fertilization were examined for the appearance of gangliosides. In Rana pipiens, gangliosides were found to appear first at the late gastrula, a stage well before any morphological appearance of a nervous system. Furthermore, at this stage and at a later stage, hatching, only two of the four major gangliosides were detected, namely, monosialoganglioside GM1 and disialoganglioside GD1a.
DEVELOPMENTAL CHANGES OF CHOLINE ACETYLTRANSFERASE (ChAc) ACTIVITY IN CHICK EMBRYO SPINAL AND SYMPATHETIC GANGLIA
Authors: Marchisio P. C. , Consolo Silvana
Published: October 2006

Abstract— The ChAc activity of spinal and sympathetic ganglia was measured throughout the embryonic life of the chick.

In spinal ganglia, the ChAc activity reached a first peak when the maximal proliferation of neuroblasts occurred. Then, the relative ChAc activity decreased. After the 12th day of incubation, the enzyme activity increased again and reached a second peak on the 16th day.

In sympathetic ganglia, the general course of the development of ChAc activity was similar to spinal ganglia. However, higher enzymic activity was found. Furthermore, the earlier peak of ChAc activity occurred 48 hr later than the corresponding peak in spinal ganglia.

The behaviour of ChAc activity in these two areas of the developing nervous system is interpreted as a function of their histogenesis.
CORRELATION BETWEEN [U‐14C]GLUCOSE METABOLISM AND FUNCTION IN PERFUSED CAT BRAIN
Authors: Otsuki S. , Watanabe S. , Ninomiya K. , Hoaki T. , Okumura N.
Published: October 2006

Abstract— In brain perfusion experiments conducted with blood containing [U‐14C]glucose the relative specific activity (RSA) of blood glucose carbon incorporated in brain intermediate metabolites was measured. It was demonstrated that the so‐called metabolic pattern of Geiger is not constant, but it bears a close relation to the function of the brain. The results of the study may be summarized briefly as follows.

(1) In a group (A) of cats with a high level of brain function, the RSA of lactic acid was 75 per cent; that of glutamic acid 80 per cent; aspartic acid 75 per cent; glutamine 61 per cent; GABA 43 per cent; and respiratory CO2 55 per cent. It was observed that the major part of the carbon of amino acids, such as glutamic acid and aspartic acid, which are directly associated with the tricarboxylic acid cycle are derived from blood glucose.

(2) In a group (B) showing a low level of brain function, the RSA of each amino acid was considerably lowered. The RSA of glutamic acid and aspartic acid was about 50 per cent and that of respiratory CO2 was 27 per cent.

(3) In a group (C) with a still lower level of brain function, each amino acid as well as the respiratory CO2 had still lower RSA values.

(4) The metabolic pattern of Geiger corresponds to values obtained during low functional activity of the brain in our experiment.
ESTIMATION OF CHOLINESTERASE AND CHOLINE ACETYLTRANSFERASE IN BOVINE ANTERIOR PITUITARY, POSTERIOR PITUITARY, AND PINEAL BODY*
Authors: LaBella F. S. , Shin S.
Published: October 2006

Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were estimated colorimetrically with thiocholine (SCh) esters as substrates in homogenates of bovine anterior pituitary (AP), posterior pituitary (PP), and pineal body (PB), and the levels were referred to those of whole rat brain. The levels of BuChE were very similar in all four tissues, approximately 10.25 μm‐BuSCh hydrolysed/g tissue/hr; indicating that this enzymic activity represents a common structural component, perhaps vascular elements. Acetyl‐thiocholine (ASCh) hydrolysis by AChE for brain, PP, PB, and AP was 338, 37,24, and 6 μm/g/hr, respectively. Choline acetyltransferase (ChAc) was estimated by the formation of [14C]acetylcholine from [14C]acetyl CoA. ChAc activity of posterior pituitary was generally found to be 15–20 per cent that of brain; the activity was always lowest in the anterior pituitary and pineal body, sometimes undetectable, but generally 5–10 per cent that of brain. The basis for the interpretation that cholinergic components in the posterior pituitary are due to acetylcholme‐containing nerve endings and in anterior pituitary and pineal body to axons of sympathetic neurons was discussed.
INOSITOL CHANGES IN NERVE AND LENS OF GALACTOSE FED RATS1
Authors: Stewart M. A. , Kurien Mary M. , Sherman W. R. , Cotlier E. V.
Published: October 2006

Abstract— —(1) Major organs of rats fed a 40 per cent galactose diet for one month were surveyed for changes in free myo‐inositol. The levels were reduced only in lens and sciatic nerve.

(2) In nerve and lens the low myo‐inositol level was associated with high concentrations of galactitol and increased water content.

(3) In nerve and lens myo‐inositol levels returned towards normal during a period of 1–2 weeks in which animals were fed a regular diet again. The pattern of change showed (a) an initial lag period, and (b) return to normal after galactitol concentrations had fallen to a low level and at the same time that water content returned to normal.

(4) In nerve there were changes in scyllo‐inositol levels that paralleled those in myoinositol.

(5) The evidence suggests that the inositol changes were related to the osmotic effects of galactitol accumulation rather than to a direct inhibition of myo‐inositol synthesis or uptake.
THE MEASUREMENT OF TRIGLYCERIDE IN BRAIN AND THE METABOLISM OF BRAIN TRIGLYCERIDE IN VITRO
Authors: Rowe C. E.
Published: October 2006

Abstract—

Triglyceride has been isolated from brain by thin‐layer chromatography and determined by absorption of the carbonyl group at 1740 cm−1. The means of yields from whole mouse brain, whole rat brain, rat brain grey matter, rat brain stem, and incubated slices of rat brain cortex were 0.15–0.17 μmole/g tissue.

The distribution of fatty esters varied from preparation to preparation. Palmitate, stearate and oleate usually occurred in greatest amounts. Hydrolysis of a preparation of triglyceride from whole rat brain with pancreatic lipase indicated that palmitate was equally distributed between the α and β esters.

[1‐14C]Acetate was rapidly incorporated into triglyceride of slices of incubated rat brain cortex. When the resulting triglyceride was hydrolysed with pancreatic lipase the distribution of radioactivity amongst the hydrolysis products was consistent with both the α and β esters of the triglyceride having been radioactively labelled.
INCORPORATION OF 32P IN VITRO INTO TRIPHOSPHOINOSITIDE AND RELATED LIPIDS OF RAT SUPERIOR CERVICAL GANGLIA AND VAGUS NERVES
Authors: Yagihara Y. , Salway J. G. , Hawthorne J. N.
Published: October 2006

Abstract— Rat sympathetic ganglia, vagus nerve and sciatic nerve were each incubated with inorganic 32P for various lengths of time and the resultant labelling of their inositol lipids was measured.

At all times up to 3 hr phosphatidylinositol was the most highly labelled lipid of ganglia, while triphosphoinositide was the most active lipid of vagus and sciatic nerves. Removal of calcium ions from the incubation media had no significant effect on the incorporation of phosphate into any of the inositol lipids of sympathetic ganglia.
THE EFFECTS OF INDIVIDUAL AMINO ACIDS ON THE INCORPORATION OF LABELLED AMINO ACIDS INTO PROTEINS BY BRAIN HOMOGENATES1
Authors: Peterson N. A. , McKean C. M.
Published: October 2006

Abstract— The effects of phenylalanine and other amino acids on incorporation of several different 14C‐labelled amino acids into cerebral protein were studied in brain homogenates. Excess of some amino acids had a varied effect with different 14C‐labelled amino acids. Of the unlabelled‐labelled amino acid combinations tested the maximal inhibition was obtained with the following: (1) phenylalanine, which inhibited the incorporation of [14C]tyrosine, and (2) leucine, which inhibited incorporation of [14C]isoleucine. In both cases the inhibition occurred principally in proteins that were recovered in the 800 g and 13,000 g sediments. Only a small degree of inhibition occurred in proteins that sedimented at 100,000 g, and no inhibition occurred in proteins of the 100,000 g supernatant.
A REGIONAL STUDY OF SOME OSMOTIC, IONIC AND AGE FACTORS AFFECTING THE STABILITY OF CEREBRAL LYSOSOMES1
Authors: Sellinger O. Z. , Nordrum Linda M.
Published: October 2006

Abstract— An examination was made of the effect of changes in the osmolarity and the ionic composition of the homogenizing medium on the partition of lysosomal arylsulphatase and N‐acetylglucosaminidase of cerebral cortex, hypothalamus and thalamus of the rat. Sulphatase appeared to be more sensitive to hypotonicity than glucosaminidase, since a higher proportion of the sulphatase was released from the lysosomes into the soluble fraction of the cells from all three neuroanatomical areas examined. In the presence of 250 mM‐sucrose, supplementation with 10 mM‐Mg led to clumping of the lysosomes and their translocation into the heavy‐particulate fraction; no such effect of 10 mM‐Mg was noted in the absence of 250 mM‐sucrose.

The intracellular distribution of bound N‐acetylneuraminic acid (bound‐NANA) was also examined. The shifts observed in its intracellular localization as a result of changes in the ionic composition of the homogenizing medium rule out bound‐NANA as a structural component of the membrane of the cortical lysosome. However regional differences in the response of bound‐NANA to ionic factors were observed.

Lysosomes from cerebral cortex of adult and 12‐day‐old rats were also compared. Differences in the pattern of distribution of lysosomes in linear sucrose gradients and in response to ionic factors were uncovered.

The results support the previously enunciated concept (Sellinger and Hiatt, 1968) of a regional microheterogeneity of lysosomes and add a new, age‐related dimension to it.
EFFECTS OF CATIONS ON ISOLATED BOVINE OPTIC NERVE MYELIN1
Authors: Leitch G. J. , Horrocks L. A. , Samorajski T.
Published: October 2006

Abstract— Myelin fragments were isolated from bovine optic nerves and then exposed to solutions of NaCl, CaCl2, LaCl3 or to water. Measurements of the water content of myelin pellets and the hydrophobicity of myelin fragments indicated an apparent isoelectric point at about pH 4.0 which increased with increasing membrane counterion valence. The exposure of myelin to CaCl2 and LaCl3 solutions for 1 hr removed relatively more cholesterol and galactolipid than protein or phospholipid. The same changes were observed after 12 days of storage in all four solutions. Myelin ultrastructure was evaluated by electron microscopy after positive and negative staining. No pronounced changes in myelin ultra‐structure were seen after exposure to any of these solutions although extensive beading of the lamellae was observed and the magnitude of the major period was greater than that reported for native myelin. While differences in the physical properties of myelin after exposure to Na+, Ca++, or La+++ ions could be explained by considering the fixed charge shielding capabilities of these cations, changes of state of the membrane infrastructure could not be ruled out. At pH values above 4.0 myelin fragments behaved like a cation exchange system.
MULTIPLE SUBSTRATE DETERMINATION OF MONOAMINE OXIDASE DISTRIBUTION AND IPRONIAZID INHIBITION IN RAT BRAIN1
Authors: La Motte R. H. , Schmidt D. E. , Ruliffson W. S.
Published: October 2006

Abstract— —A variety of monoamine oxidase substrates (tyramine, dopamine, serotonin, tryptamine) have been used with and without Iproniazid inhibition to evaluate further the extent to which enzyme multiplicity may exist in various regions of rat brain. Levels of monoamine oxidase activity, as measured by ammonia production, were found to vary as a function of both brain area and kind of substrate used, in the absence as well as in the presence of Iproniazid, in vivo and in vitro. Similarity of substrate metabolizing patterns among the different brain areas, however, strongly suggests that only one kind of monoamine oxidase exists in rat brain.
PROTEIN SYNTHESIS IN ISOLATED NUCLEI FROM ADULT RAT BRAIN
Authors: Burdman J. A. , Journey L. J.
Published: October 2006

Abstract—

Nuclei from adult rat brains isolated with isotonic sucrose were incubated with [3H]leucine and later purified by centrifugation through hypertonic sucrose solutions. It was found that under these conditions, tritiated leucine was incorporated into TCA precipitable material. Protein synthesis was impaired if the nuclei were treated with the nonionic detergent Triton X‐100 or hypertonic sucrose. The presence of puromycin or cycloheximide markedly inhibited the incorporation of the radioactive amino acid. Actinomycin D and RNase did not have any effect on the incorporation. Autoradiography indicated the presence of labelled material within the nuclei and not in cytoplasmic contaminants. Glial nuclei were more actively involved in protein synthesis than neuronal nuclei.
OBSERVATIONS ON PURINE METABOLISM IN RAT BRAIN
Authors: Held Irene , Wells W.
Published: October 2006

Abstract—

Both de novo and preformed base or salvage pathways are simultaneously operative in the biosynthesis of purine nucleotides in rat brain per se. A preferential utilization of de novo precursors is demonstrated.
CHOLINE ACETYLTRANSFERASE (ChAc) ACTIVITY IN DEVELOPING CHICK OPTIC CENTRES AND THE EFFECTS OF MONOLATERAL REMOVAL OF RETINA AT AN EARLY EMBRYONIC STAGE AND AT HATCHING
Authors: Marchisio P. C.
Published: October 2006

Abstract—

The choline acetyltransferase (ChAc) activity was measured in the optic centres of chick embryos after early removal of the optic cup and of young chicks after monolateral extirpation of the right eyeball after hatching. The contralateral optic lobes were thus deprived of their complement of retinal fibres. The following results were obtained: in chick embryos the ChAc was slightly lower in the deafferented lobe between the 10th and the 14th day of incubation; between the 14th and the 17th day a critical fall in activity was observed leading to a significant ChAc loss of 71 per cent. In eye deprived chicks no significant change in total ChAc activity occurred during the first postoperative month; significant changes were found only in the second month.

The results reached so far suggest that removal of retinal fibres does not cause short term changes in optic centre ChAc in either the embryo or the chick. ChAc contained in nerve cell bodies seems independent of synapses and its behaviour is interpreted as a reflection of metabolic disturbance of the centre.
ALKALINE PHOSPHODIESTERASE ACTIVITY OF GOAT BRAIN CORTEX RIBOSOMES
Authors: Datta R. K. , Ghosh J. J. , Bhattacharyya K. C.
Published: October 2006

Abstract—

The ribosome preparation of goat cerebral cortex was found to possess acid and alkaline phosphodiesterase (PDase) activities, the alkaline PDase activity was greater. The alkaline PDase activity increased sharply between pH 8 and 9 and showed maximum activity between 35° and 40°. The alkaline PDase lost about half of its activity on heating the ribosome preparation at 83° for 5 min. Storage at low temperature or freezing and thawing did not cause significant loss of enzymic activity, but prolonged dialysis beyond 24 hr in the cold against magnesium‐cacodylate buffer caused some loss of activity. Copper, cobalt, inorganic phosphate ions, EDTA, urea and detergents were found to be inhibitors of the PDase activity. Differential inactivation in the presence of arsenate and zinc ions suggests the distinctness of the PDase activity from the phosphomonoesterase (PMase) activity of the ribosome preparation. The enzyme appeared firmly bound to ribosomal particles and attempts to solubilize it were unsuccessful.
BRAIN SEROTONIN CHANGES IN PHENYLALANINE‐FED RATS: SYNTHESIS STORAGE AND DEGRADATION1
Authors: Yuwiler A. , Geller E.
Published: October 2006

Abstract—

The brain serotonin levels of rats maintained on a 5 % phenylalanine diet rose more slowly (0.18 μ g/g brain/hr) after administration of a monoamine oxidase inhibitor than did serotonin levels of controls (0.41 μ g/g brain/hr). The rate of brain serotonin decline following reserpine or dimethylaminobenzoyl methyl reserpate was the same for both groups as was basal monoamine oxidase activity. Brain uptake of monoamine oxidase inhibitor was also the same for both groups. It was concluded that the decrease in brain serotonin levels in phenylalanine‐fed animals was due to decreased serotonin formation rather than enhanced degradation. On the basis of available data it was concluded that both hydroxylase inhibition and inhibited precursor transport were involved.
CHANGES IN THE HYPOTHALAMO‐NEUROHYPOPHYSICAL NEURO‐SECRETORY MATERIALS OF RATS DURING DIFFERENT PHASES OF MORPHINE ADMINISTRATION
Authors: Ray A. K. , Ghosh J. J.
Published: October 2006

Abstract—

Acute morphine treatment of rats increased the concentration of neuro‐secretory material in the posterior pituitary. These changes were accompanied by the presence of more neurosecretory materials in the axons of the hypothalamic supraoptic and paraventricular neurons and in the hypothalamic capillaries and sinuses. In the perikarya of the hypothalamic supraoptic and paraventricular neurons, the neurosecretory material is in a dispersed state.

Following chronic morphine treatment, neurosecretory material was almost absent from the posterior pituitary, whereas in the perikarya of the supraoptic and paraventricular neurons, congestion of neurosecretory material is observed which is accompanied by the absence of the neurosecretory material from the axons arising from the supraoptic and paraventricular nuclei and from the hypothalamic capillaries and sinuses.

During nalorphine‐induced abstinence, there was sudden reappearance of the neurosecretory material in the posterior pituitary along with the appearance of neurosecretory material in the hypothalamic neurosecretory neuronal tracts, blood capillaries and sinuses together with the dispersion of the neurosecretory materials from the hypothalamic neurosecretory neurons.
BOUND ACETYLCHOLINE IN THE NERVE ENDING PARTICLES1
Authors: Takeno K. , Nishio A. , Yanagiya I.
Published: October 2006

Abstract—

The bound ACh of rabbit brain tissue homogenate was studied with the French press technique by means of which nerve endings can be ruptured under isotonic condition.

Two fractions of B‐ACh, stable and labile were obtained which were roughly equal in amount. The yield of B‐ACh after disruption of nerve ending particles was about 28 per cent of the initial total ACh and higher than that formed after the hypotonic disruption.

The results support the view that the stable fraction of B‐ACh is enclosed inside the vesicle membrane, while the labile fraction is present in the cytoplasm of the cell.

ACh released from such intact vesicle fractions was roughly parallel to the ionic strength of the solution at 0°, without relation to the nature of the ion itself.

Electronmicroscopic examination with PTA showed that the vesicles released by the French press technique were largely intact, although the nerve ending particles were completely disrupted by the same treatment.
32P INCORPORATION INTO DIFFERENT MEMBRANOUS STRUCTURES SEPARATED FROM RAT CEREBRAL CORTEX1
Authors: Lapetina E. G. , Arnaiz Georgina Rodríguez De Lores , Robertis E. De
Published: October 2006

Abstract— The time course of incorporation, between 3 hr and 16 days, of ortho[32P]phosphate into different membranous structures isolated from the rat cerebral cortex was studied. After subarachnoideal administration into the CSF it was found that myelin, mitochondria, microsomes and purified nerve‐ending membranes and synaptic vesicles incorporate 32P at the same rate. Most of the individual phospholipids of the synaptic vesicles and nerve‐ending membranes also have similar rates of incorporation. Only phosphoinositides and/or phosphatidylserine may have a more rapid metabolism. The incorporation of 32P into phosphoproteins follows a different pattern from that of the phospholipids. The intraperitoneal route is less effective in the 32P incorporation and differences among the fractions may be found.

These results are discussed in relation to the problem of the blood‐brain barrier to phosphate and to the labelling of individual phospholipids in the different membranes.
FREE AMINO ACIDS OF FETAL BRAIN
Authors: Carver M. J.
Published: October 2006

Abstract— Injection of each of the branched chain amino acids into maternal rats from the 14th to 21st day of pregnancy resulted in increased levels of these compounds in fetal serum. Furthermore, these amino acids were found in high concentration in fetal brain. The elevated levels of the branched chain amino acids were associated with a disturbance of the free amino acid pool in the brain. Isoleucine appeared to have the greatest effect in depressing the other amino acids.
A FLOW‐THROUGH TISSUE HOMOGENIZER FOR THE LARGE SCALE PRODUCTION OF BRAIN HOMOGENATES
Authors: Rodnight R. , Wynter Coral V. A. , Cook C. N. , Reeves R.
Published: October 2006

Abstract— The construction of a flow‐through homogenizer suitable for making homogenates of brain on a large scale is described. Using grey matter from ox brain as starting material, the performance of the machine has been compared with a conventional test tube homogenizer.
HISTOCHEMICAL DEMONSTRATION OF ACID RIBONUCLEASE IN THE CENTRAL NERVOUS SYSTEM
Authors: Ghosh Swati , Ghosh J. J.
Published: October 2006

Abstract— The staining pattern of acid ribonuclease activity in the nervous tissues of rats has been studied with different fixatives and incubation media. Certain modifications in the method adopted (Vorbrodt, 1961) produced a definite improvement in the localization as well as distinct subcellular distribution at the pHs studied. The modifications introduced consisted of preincubation of tissue sections with prostatic acid phosphatase, omission of acid phosphatase from the standard incubation medium and its addition at a later stage of incubation. This avoids much of the diffused cytoplasmic and filamentous background staining at pH 5.2–5.8, eliminates the irregular nuclear staining at pH 4.5 and replaces the strong nuclear positivity at pH 5.2 by a fine granular dispersion.

A study of the enzyme activity of subcellular fractions at the different pHs used was performed to confirm the histochemical localization.
STUDY OF RNA IN SUBCELLULAR FRACTIONS FROM RAT BRAIN: SIMULTANEOUS INCORPORATION OF [14C]URIDINE AND [3H]METHYL‐l‐METHIONINE
Authors: Saborio J. L , Alemán V
Published: October 2006

Abstract— By using a combination of subcutaneous and intraventricular injections of [14C]uridine and [3H]methyl‐l‐methionine we have obtained maximum incorporation in about 40 min of both radioactive precursors into nuclear RNA from rat brain. In this nuclear fraction we found at least two different types of RNA that were rapidly labelled. One of them incorporated both [14C]uridine and [3H]methyl groups and seemed to correspond to species of rRNA and their precursors. The other RNA fraction was less methylated or non‐methylated and exhibited sedimentation coefficients distributed along a continuous 8–30 % sucrose density gradient. At least part of the latter type of RNA very probably was mRNA, but much of it must conespond to a different RNA similar to that recently described in HeLa cells by Penman, Vesco and Penman (1968).

We also found that labelled 185 and 285 rRNA components began leaving the nucleus for the cytoplasm within 24 to 33 min after the radioactive precursors had been injected, and, in the cytoplasmic fraction, the patterns of incorporation for [14C]uridine and [3H]‐methyl groups were similar for the 18S and 28S rRNA components. We estimate that in this fraction of rat brain the 18S rRNA component was 1·4 times more methylated than the 28S component. We also detected a lower sedimentation coefficient for the non‐ or slightly methylated, species of soluble RNA found in the cytoplasmic fraction.
ENZYMATIC FLUOROMETRIC DETERMINATION OF ACETYLCHOLINE IN BIOLOGICAL EXTRACTS1
Authors: O'Neill John J , Sakamoto Tetsuhiko
Published: October 2006

Abstract— Acetylcholine was determined fluorometrically by the following enzymic reactions:

(1) ACh = Acetate + Choline

(2) Acetate + ATP + CoASH = Acetyl‐SCoA + AMP + PPi

(3) Malate + NAD+= Oxalacetate + NADH

(4) Oxalacetate + Acetyl‐SCoA = CoASH + Citrate

The fluorescence produced by NADH was stoichiometric with the ACh present and the citrate formed. The complete system contained acetylcholinesterase (EC 3.1.1.7), acetyl‐CoA synthetase (EC 6.2.1.1), malate dehydrogenase (EC 1.1.1.37), and citrate condensing enzyme (EC 4.1.3.7). The acetyl‐CoA synthetase was rate limiting in the system.

Authentic samples of ACh (10−8 to 10−9mol) were measured with ±5 per cent reproducibility; this corresponds to the content of an 80 mg (fresh weight) sample of brain. Tissue levels of ACh in this concentration range, within normal biological variation, were determined with ±15 per cent reproducibility. The method can also be employed to measure acetate and acetyl‐SCoA with the same degrees of sensitivity and reproducibility. The method can be used to measure ‘total’ and ‘bound’ ACh and thus to estimate ‘free’ ACh, by varying the extraction procedure. Values obtained in the manner described agree with those previously reported in the literature.

Troublesome fluorescence in brain extracts was effectively removed with acid‐washed Florisil.
RETENTION AND EXCHANGE OF POTASSIUM IN A SYNAPTOSOMAL FRACTION OF MOUSE BRAIN
Authors: Weinstein H , Kuriyama K
Published: October 2006

Abstract— Myelin, synaptosomal and mitochondrial fractions obtained from homogenates of whole mouse brain contain K+ which can exchange with 42K+ at 2º in 0·32 m‐sucrose. The content and rates of exchange of K+ were greater at pH 8·2 than at 6·1. In the synaptosomal preparations, the rates of exchange and content of 42K+ and K+ declined progressively with decreasing pH.

Of the total synaptosomal K+, 95 per cent could exchange with external 42K+. At pH 7·5, 20 per cent of the K+ and 78 per cent of the Na+ appeared to reside in osmotically insensitive pools. Synaptosomal K+ at 2º was slowly displaced by NaCl (0·18 m) and the rate of exchange between 42K+ and K+ was retarded. KCI (0·18 m) did not readily displace endogenous Na+. Synaptosomal K+ exchanged with exogenous K+ more rapidly than with exogenous Na+.

These observations have been discussed in terms of possible roles for ion exchange as the principal means by which K+ traverses the plasma membrane at 2º.
DIFFERENCES IN THE REGULATION OF TYROSINE AMINOTRANSFERASE IN BRAIN AND LIVER
Authors: Fuller Ray. W
Published: October 2006

Abstract— l‐Tyrosine:2‐oxoglutarate aminotransferase (EC 2.6.1.5) activity in rat brain is not regulated in the same way as in rat liver. No diurnal rhythm in the activity of the cerebral enzyme was found in rats fed ad lib. although there was a marked diurnal variation in the activity of the hepatic enzyme. In adrenalectomized rats, hydrocortisone and glucagon induced the enzyme in liver but had no effect on the enzyme in brain. In normal rats, treatment with reserpine or exposure to cold elevated the activity of the hepatic enzyme without affecting the enzyme in brain. Thus, the tyrosine aminotransferase of brain differed from the enzyme in liver since it did not exhibit diurnal variations of activity and was not affected by hormones, drugs, or stress.
METABOLISM OF HIGHLY BASIC PROTEINS OF RAT BRAIN DURING POSTNATAL DEVELOPMENT
Authors: Gaitonde M. K , Martenson R. E
Published: October 2006

Abstract— (1) The encephalitogenic basic protein obtained from adult rat brain by treatment with 0·03 N‐HCl was demonstrable in the brain on the 10th day after birth. It showed a marked increase in quantity during the phase of active myelination.

(2) The proteins extracted under similar conditions from 5‐day old rat brain contained several highly basic proteins other than the encephalitogenic basic protein. These basic proteins, which were electrophoretically similar to highly basic proteins extracted similarly from adult rat liver, are histones.

(3) For metabolic studies the entire group of highly basic proteins in the acid extract was obtained after one‐step adsorption of other proteins on DEAE‐cellulose equilibrated at pH 9·8

(4) After injection of [14C]lysine the fractions containing highly basic proteins, water soluble non‐basic proteins and other tissue proteins of the brain showed higher relative specific radioactivities during the period 1–10 days after birth than during later stages of postnatal development. The fraction containing proteolipid protein, another myelin protein, showed a low relative specific radioactivity throughout the whole period of postnatal development. The relative specific radioactivity of proteolipid protein was somewhat higher in young than in adult rat brain.
A NEW PROCEDURE FOR THE MEASUREMENT OF ACID‐SOLUBLE GLUTAMINE OF TISSUE WITH PARTICULAR REFERENCE TO THE BRAIN
Authors: Dobkin J. , Marton M.
Published: October 2006

—A simple method is described for the measurement of free brain glutamine by spectrophotometric means, without prior separation by either paper or column chromatography. Through the application of this method, it was also possible to obtain an approximate value for the combined concentrations of glutamic acid, y‐aminobutyric acid and glutathione in brain.
SOME PROPERTIES OF GLUTAMATE DECARBOXYLASE AND THE CONTENT OF PYRIDOXAL PHOSPHATE IN BRAINS OF THREE VERTEBRATE SPECIES
Authors: Tapia R. , Pasantes Herminia , Massieu G.
Published: October 2006

—Some properties of glutamate decarboxylase (GAD) were studied in the brain of the carp (Carassius auratus), the pigeon (Columbia livia) and the mouse (Mus musculus). The optimum pH for GAD in the three species was 6·3‐6·5. In the three species studied, GAD activity of brain homogenates in water was higher than that of homogenates in buffer. The supernatant from homogenates in Triton‐X‐100 gave an enzyme preparation which showed greater activation by pyridoxal phosphate than those obtained from complete water or buffer homogenates or from the supernatant of Water homogenates.

In the absence of pyridoxal phosphate, the activity of carp GAD was considerably lower than that of mouse or pigeon GAD. The addition of pyridoxal phosphate resulted in a much greater activation of carp GAD than that of pigeon or mouse GAD. Pyridoxal phosphate content was also measured in brains of the species studied. The difference between coenzyme levels in carp and mouse was very small in comparison to the difference in GAD activity in the absence of exogenous coenzyme. The pyridoxal phosphate content of pigeon brain was higher than that of the other two species.
COMPARTMENTATION OF CITRIC ACID CYCLE METABOLISM IN BRAIN: EFFECT OF AMINOOXYACETIC ACID, OUABAIN AND Ca2+ ON THE LABELLING OF GLUTAMATE, GLUTAMINE, ASPARTATE AND GABA BY [1‐14C]ACETATE, [U‐14C]GLUTAMATE AND [U‐14C] ASPARTATE1
Authors: Berl S. , Clarke D. D. , Nicklas W. J.
Published: October 2006

—(1) The effects of aminooxyacetic acid, ouabain and Ca2+ on the compartmentation of amino acid metabolism have been studied in slices of brain incubated with sodium‐[1‐14C]acetate, l‐[U‐14C]glutamate and l‐[U‐14C]aspartate as tracer metabolites.

(2) Aminooxyacetic acid (10‐3 m) inhibited the labelling of aspartate from [14C]acetate and [14C]glutamate, as well as the incorporation of label from [14C]aspartate into glutamate and glutamine. It also inhibited the labelling of GABA from all three radioactive precursors, as would be anticipated if there was inhibition of several transaminases as well as glutamate decarboxylase. The RSA of glutamine labelled from [1‐14C]acetate was increased. This finding indicated that the glutamate pool which is utilized for glutamine formation is associated with glutamate dehydrogenase, and this enzyme appears to be related to the ‘synthetic tricarboxylic acid cycle’. AOAA exerted its major inhibitory effects on the citric acid‘energy cycle’with which transaminases are associated.

(3) Ouabain (10‐5 m) inhibited the labelling of glutamine to a much greater extent than the labelling of glutamate from [1‐14C]acetate. It also caused leakage of amino acids from the tissue into the medium. Its effect on the glutamate–glutamine system was interpreted to be a selective inhibition of the 'synthetic’citric acid cycle.

(4) The omission of Ca2+ from the incubation medium was associated with formation of glutamine with RSA less than 1·0 when labelled from [U‐14C]glutamate, [U‐14C]aspartate and lower than normal when labelled from [1‐14C]acetate.
FOLATE LEVELS IN DEVELOPING MOUSE BRAIN1
Authors: McClain L. D. , Bridgers W. F.
Published: October 2006

Abstract— The folate coenzymes of mouse brain underwent quantitative and qualitative changes during the first few weeks after birth. The total folate coenzymes per unit wet weight declined by approximately 60 per cent. In the newborn brains a relatively small proportion of the total folates were poly‐γ‐glutamyl derivatives, but the percentage of the total folates in these forms increased as the brain matured.
THE REGIONAL DISTRIBUTION OF SIALOGLYCOPROTEINS, GANGLIOSIDES AND SIALIDASE IN BOVINE BRAIN
Authors: Roukema P. A. , Heijlman J.
Published: October 2006

Abstract— Sialoglycoproteins and gangliosides were characterized in various bovine brain regions by determining the amount of sialic acid. Expressed per g dry weight, the gangliosidic sialic acid ranged from 11·20 to 1·93 μmol and the glycoprotein sialic acid from 8·93 to 1·84 μmol in grey and white matter respectively (values not corrected for incomplete release and breakdown during hydrolysis). Both the sialoglycoproteins and the gangliosides occur in highest concentration in areas predominating in neuronal cell bodies (cerebral grey, cerebellar grey, caudate nucleus). The lowest concentrations are found in those areas, consisting largely of myelinated fibre tracts and glial cells (pons, medulla, corpus callosum, cerebral white). Relative to the gangliosides the sialoglycoproteins are somewhat more concentrated in white matter.

The sialidase activity was investigated with endogenous substrate as well as with additional gangliosides or sialoglycopeptides. In all conditions the activity was much greater in grey matter than in white matter. The regional sialidase distribution more or less parallels the distribution of sialic acid in the various regions. At high substrate level the sialoglycopeptides inhibit the sialidase activity. There are indications that gangliosides are a far better substrate for brain sialidase than glycoproteins or glycopeptides. The possible significance of this phenomenon is discussed.
THE COMPARTMENTATION OF GLUTAMATE AND ITS METABOLITES IN FRACTIONS OF NEURON CELL BODIES AND NEUROPIL; STUDIED BY INTRAVENTRICULAR INJECTION OF [U‐14C]GLUTAMATE
Authors: Rose S. P. R.
Published: October 2006

Abstract—

The in vivo metabolism of glutamate in rat neuron cell bodies and neuropil was studied after intraventricular injection of (U‐14C)glutamic acid followed by separation of the tissue into neuronal and neuropil fractions.

The losses of amino acid and of radioactivity during the fractionation were equivalent. Recoveries were: glutamate, 32; glutamine, 15; aspartate, 25; GABA, 41; alanine, 30 per cent. In the washed cell fractions glutamine was 45 per cent and alanine 132 per cent higher in the neuronal fraction, glutamate was 62, GABA 77 and aspartate 95 per cent of neuropil levels. This contrasted with results obtained previously for in vitro incorporation. Calculation from these results indicated that 28 per cent of the original cell suspension was neuronal, 72 per cent neuropil. In the final cell preparations, 29 per cent of the neuron cell bodies and 26 per cent of the neuropil were recovered.

Specific activity of glutamate in the neuronal fraction 15 min after injection was higher than in the original suspension, but had declined to 30 per cent of its initial value by 2 h. In the neuropil, specific activity of glutamate was below that of the cell suspension at 15 min, but at later times rose above it by up to 40 per cent.

Radioactivity was detected in aspartate and glutamine 15 min after injection and GABA by 60 min after injection. In the original cell suspension the specific activity of glutamine was higher than that of glutamate at all times (the Waelsch effect) but aspartate and GABA were lower than glutamate.

In the neuronal fraction the specific activity of glutamine was below that of glutamate at all times, indicating a precursor‐product relationship. In the neuropil fraction, glutamine specific activity remained above glutamate for the first hour.

These results are discussed in relation to the interpretation of the Waelsch effect in terms of metabolic compartmentation.
BIOCHEMICAL CHARACTERIZATION OF β‐N‐OXALYL‐l‐α,β‐DIAMINOPROPIONIC ACID, THE LATHYRUS SATIVUS NEUROTOXIN AS AN EXCITANT AMINO ACID
Authors: Cheema P. S. , Padmanaban G. , Sarma P. S.
Published: October 2006

Abstract— β‐N‐Oxalyl‐l‐α,β‐diaminopropionic acid (ODAP), the toxin isolated from the seeds of Luthyrus sativus produces head retraction, tremors and convulsions when injected into a variety of experimental animals. In 12‐day‐old rats, it has been found that the convulsive behaviour is accompanied by profound biochemical changes in the brain. The brain homogenates prepared from ODAP injected animals show a higher rate of respiration. There is a decrease in the brain glucose, glycogen, ATP, phosphocreatine and acetylcholine levels of the convulsing animals. The inorganic phosphate, lactic acid and acetylcholineesterase levels increase. These results establish that ODAP is a typical convulsant.
THE EFFECT OF CALCIUM ON GANGLIOSIDE SOLUBILITY
Authors: Kruger S. , Mendler M.
Published: October 2006

Abstract—

Gangliosides were extracted by various procedures from acetone powder prepared from grey matter of cattle brain. The mixtures of gangliosides, containing 24–26% N‐acetylneuraminic acid (NANA), were dissolved in chloroform‐methanol. Upon addition of aqueous solutions of Ca2+, the amount of gangliosides (and Ca2+) passing into the lower phase of the two‐phase solvent system was a linear function of the product of the initial concentrations of Ca2+ and ganglioside‐NANA. It was also a function of the initial stoichiometric ratios of ganglioside‐NANA to Caa+. In accordance with previous reports, no gross differences of composition between the initial mixture of gangliosides and the calcium‐solubilized portion could be detected by glass‐fibre chromatography.
LIPID METABOLISM IN BRAIN TISSUE EXPLANTS1
Authors: Menkes J. H.
Published: October 2006

Abstract— Tissue explants from frontal lobes of rat brain were used for the study of cerebral fatty acid metabolism. After tissues had been maintained in serum‐supplemented medium, a lipid‐free medium was substituted and metabolic studies were carried out. Under these conditions explants continued to take up lipid precursors for at least 48 h, as judged by incorporation of dl‐[2‐14C]mevalonic acid into cellular lipids. [l‐14C]Stearic acid and [l‐14C]palmitic acid were bound to cells as the free fatty acids, or incorporated into neutral lipids (particularly triglycerides), glycolipids and phospholipids. In the galactolipid fraction, cerebrosides were the principal radioactive lipids. Choline phosphoglycerides, ethanolamine phosphoglycerides, inositol phosphoglycerides and serine phosphoglycerides were the principal radioactive phospholipids. Fatty acids were incorporated into cellular lipids either unchanged or after desaturation, chain elongation, or both. Maximum incorporation of stearate occurred in tissues derived from 3‐day‐old animals. With increasing age the uptake of fatty acid dropped sharply.

When the labelling of lipids as a function of time was followed in 3‐day‐old animals, triglycerides and choline phosphoglycerides were the first fractions to take up labelled stearate. Labelling of cerebrosides occurred slowly, only becoming evident after 24 h. These studies exemplify the usefulness of tissue explants for prolonged metabolic studies in normal and pathological specimens of brain.
THE INHIBITION OF PROTEIN SYNTHESIS IN A RAT BRAIN SYSTEM BY ETHIONINE IN VITRO AND IN VIVO1
Authors: Lamar C.
Published: October 2006

Abstract— An amino acid incorporating system from rat brain has been used to study in vitro four aspects of protein synthesis: amino acid‐AMP‐enzyme complex formation; amino acid‐tRNA synthesis; amino acid incorporation into protein and protein synthesis from presynthesized amino acid‐tRNA. Ethionine (0.5 mm) inhibited the system and the inhibition appeared to be in the formation of amino acid‐tRNA. The inhibition in vitro was independent of the sex of the animal from which the system was derived. Pretreatment of animals in vivo with ethionine yielded in females only preparations deficient in incorporating capacity when tested in vitro. Exchange experiments demonstrated that the defect was in the pH 5 enzymes and not in the ribosomes. The inhibition in vitro was not reversed by addition of ATP and appeared to be competitive with the amino acid substrate.
INCREASED CEREBRAL EXCITABILITY CAUSED BY p‐CHLOROPHENYLALANINE IN YOUNG RATS
Authors: Prichard J. W. , Guroff G.
Published: October 2006

—Single intraperitoneal doses of p‐chlorophenylalanine (p‐CP; 100 mg/kg or more), lowered the threshold of flurothyl‐induced seizures in 1‐ and 2‐week old rats after 24 h, but not after 4 or 72 h. In older rats there was no change in cerebral excitability after a single dose, but the seizure threshold was lowered after several daily doses. Rats given p‐CP in lower doses daily from birth exhibited lowered seizure thresholds only until 3‐4 weeks of age.

Depletion of brain serotonin and inhibition of liver phenylalanine hydroxylase by p‐CP exhibited time courses and dose responses similar to those reported for older animals. Activity of phenylalanine hydroxylase returned to normal more rapidly than the content of serotonin after a dose of p‐CP, and recovery of normal seizure threshold seemed to be more closely associated with recovery of the hepatic enzyme than with restoration of the brain amine. It appears, therefore, that hyperphenylalanemia or some consequence of it may be an important factor contributing to increased cerebral excitability in p‐CP intoxication and possibly in clinical phenylketonuria and that depletion of brain serotonin may not be the only or even the predominant cause of the changes in cerebral excitability in these conditions.
THE EFFECTS OF UNDERNUTRITION UPON THE ENERGY RESERVE OF THE BRAIN AND UPON OTHER SELECTED METABOLIC INTERMEDIATES IN BRAINS AND LIVERS OF INFANT RATS1
Authors: Thurston Jean Holowach , Prensky A. L. , Warren Sheila K. , Albone K.‐R.
Published: October 2006

—Rats undernourished from the first to the ninth day of life exhibited no decrease in the energy reserve (P‐creatine, ATP, glucose and glycogen) of the brain, although they underwent a 41 per cent decrease in body weight. The apparent increase in the cerebral levels of glucose‐6‐phosphate and the decreases in hepatic glucose and lactate in the starved animals were probably a consequence of the fact that they froze faster than the control animals rather than of any essential differences in vivo. However, decreases in cerebral glutamate (11 per cent) and hepatic glutamate (33 per cent) in the undernourished animals cannot be explained on this basis. Possible explanations for this decrease in cerebral glutamate content are: a decreased supply of glutamate from the liver, a decreased synthesis of glutamate by the brain, or an increased use of glutamate as an energy source. Since levels of glutamate in the brain increase progressively during the first weeks of life, another interesting possibility is that the lower level of cerebral glutamate in undernourished rats represents a biochemical indicator of a delay in the maturation of specific morphological components which are rich in glutamate and are characteristic of the brain.
A SENSITIVE RADIOIMMUNOASSAY FOR 7S NERVE GROWTH FACTOR ANTIGENS IN SERUM AND TISSUES
Authors: Johnson D. G. , Gorden P. , Kopin I. J.
Published: October 2006

Abstract—

A radioimmunoassay was developed which can measure accurately concentrations of mouse 7S nerve growth factor antigens (NGFA) as low as 3·0 ng/ml in serum or tissue homogenates. Extremely large amounts of presumed nerve growth factor were found in the submaxillary gland; but considerable quantities were also present in mouse serum, kidney, adrenal gland and vas deferens. Heart, spleen, liver and muscle contained less of the presumed nerve growth factor, and only small amounts were recovered from brain. Rat adrenal gland and serum from rats, guinea pigs and man contained much less immunologically reactive material. The level of presumed nerve growth factor in the mouse heart was highest at birth and decreased slowly during maturation. In the mouse submaxillary gland the content of presumed nerve growth factor increased rapidly after 2 weeks of postnatal age, with higher levels found in male animals. Destruction with 6‐hydroxydopamine of the sympathetic nerves in the hearts of newborn or adult mice did not significantly alter the amount of presumed nerve growth factor recovered in the heart.