bluuebunny/crossref_metadata_2025 huggingface dataset:
TRIPHOSPHOPYRIDINE NUCLEOTIDE‐DEPENDENT ENZYMES IN THE DEVELOPING SPINAL CORD OF THE RABBIT 1, 2
Authors: Luine V. N. , Kauffman F. C.
Published: December 2006

Abstract— Total lipid and the activity of five enzymes closely related to the generation of NADPH have been measured in the anterior horn region and dorsal columns of rabbit spinal cord during the period of rapid myelination. Lipid deposition progressed to a much greater extent in the dorsal columns than in the anterior horn region; however, the age at which one‐half of the total adult level of lipid accumulated in both regions was the same, i.e. 19‐20 days after birth. During the first 15 days of postnatal development of the dorsal columns, glucose‐6‐phosphate dehydrogenase changed in parallel with lipid content; however, in the anterior horn region changes in lipid were not accompanied by increases in glucose‐6‐phosphate dehydrogenase. In contrast to changes in glucose‐6‐phosphate dehydrogenase, the activity of malic enzyme increased in the anterior horn region but remained relatively constant in the dorsal columns during development. The activities of two other enzymes of the pentose phosphate pathway, 6‐phosphogluconate dehydrogenase and transketolase, measured at various intervals after birth, did not directly parallel changes in the activity of glucose‐6‐phosphate dehydrogenase in the dorsal columns. In both areas of the developing spinal cord the activity of NADP+‐dependent isocitrate dehydrogenase was greater than the activities of the other three dehydrogenases but it did not parallel changes in lipid content of either region. A relationship between the requirements for reducing equivalents and the activities of the four NADP+‐dependent dehydrogenases is suggested by the finding that both areas of the adult spinal cord contained lower activities of these enzymes than those observed during the initial 26 days of development. The differences noted in the two areas of the spinal cord during development suggest that mechanisms for the generation of NADPH differ in gray and white matter.
DEVELOPMENTAL CHANGES IN Na+, K+ AND ATP AND IN THE LEVELS AND TRANSPORT OF AMINO ACIDS IN INCUBATED SLICES OF RAT BRAIN
Authors: Piccoli F. , Grynbaum Alice , Lajtha A.
Published: December 2006

Abstract—

Upon incubation, slices of brain tissue took up fluid; the degree of swelling increased with increasing age. No sweiling occurred in slices from foetal brain. Since this swelling was associated with increases in the inulin space, the percentage of inulin space in slices at the end of incubation increased during brain development.

Most of the capacity for ion transport seemed to be absent from foetal brain. In vivo and in slices, Na+ was very high and K+ was very low in comparison to levels at other ages. There was a rapid change around birth, but no significant change at later ages. Upon incubation, Na+ levels increased in other slices, but not in slices of foetal brain.

Upon incubation of the slices, ATP levels were restored to levels close to those in the living brain; there were no significant alterations in available energy during development to explain changes in amino acid transport.

The composition of the free pool of cerebral amino acids in vivo changed with development, with some compounds (glutamic acid and related compounds) increasing, others (mostly‘essential’amino acids) decreasing, with age. These changes were not linear with time, and the level of a compound might exhibit several peaks during development.

The uptake (influx) of taurine, glutamate and glycine into brain slices increased rapidly during the foetal and early neonatal periods, reached a maximum between 2 and 3 weeks of postnatal age and then declined to adult levels. The levels of steady‐state uptake with glycine also exhibited a maximal peak at 2‐3 weeks of postnatal age. Steady‐state uptake of taurine and glutamate reached adult levels by about 3 weeks of age.

The pattern of inhibition of amino acid transport by two specific amino acid analogues changed during development for some amino acids (GABA, glycine and glutamate), indicating an alteration in substrate specificity.

The results demonstrate complex changes in cerebral amino acid transport during development, with several maxima or minima and with changes in specificity for at least some compounds.
DEVELOPMENTAL PATTERNS OF SULPHATE ACTIVATION AND PHENOLSULPHOTRANSFERASE IN RAT BRAIN1
Authors: Jansen G. S. I. M. , Elk R. Van , Kempen G. M. J. Van
Published: December 2006

Abstract— The formation of active suphate has been assayed in developing rat brain, the activity of the enzyme system being maximal at birth and thereafter decreasing gradually. The activity of phenolsuphotransferase, present in rat brain, is minimal at birth and increases gradually to the adult value.
ACCUMULATION OF ADENOSINE 3′,5′‐MONOPHOSPHATE IN BRAIN SLICES: INTERACTION OF LOCAL ANAESTHETICS AND DEPOLARIZING AGENTS
Authors: Shimizu H. , Takenoshita M. , Huang M. , Daly J. W.
Published: December 2006

Abstract— Membrane depolarizing agents such as veratridine, ouabain and high concentrations of potassium ions elicit a remarkable accumulation of cyclic AMP in brain slices incubated in vitro, and this accumulation, but not that elicited by biogenic amines, is prevented by a membrane stabilizer, cocaine. The effect of various local anaesthetics (compounds which are known to stabilize the membrane of peripheral sensory nerves) on the accumulation of cyclic AMP elicited by depolarizing agents in incubated slices of guinea pig brain has now been examined. At optimal concentrations the anaesthetics inhibited by more than 95 per cent the accumulation of cyclic AMP elicited with veratridine, ouabain, and high concentrations of potassium ions. The order of the inhibitory potency vs. veratridine was: dibucaine (ED50= 9.5 ± 10−6 M) > tetracaine > cocaine (ED50= 1·3 ± 10−4 M) > lidocaine > procaine (ED50= 1.7 ± 10−3M). This order is consistent with the order of their local anaesthetic potency, but is not consonant with the order of the relative toxicity of these agents when used as spinal anaesthetics.
EFFECTS OF ANOXIA IN VITRO ON CELLULAR RESPIRATION OF BRAIN CORTEX
Authors: Phizackerley P. J. R. , Fixter L. M.
Published: December 2006

Abstract— –Anaerobic preincubation of slices of brain cortex from adult rats in saline at 37°C, but not at 20°C, impaired their capacity to oxidize glucose and other substrates. This effect was to a large extent prevented by including either glucose + oxaloacetate, or l‐glutamine +l‐aspartate +α‐oxoglutarate in the medium during anaerobic preincubation, and in addition the anaerobic uptake of water by the tissue was decreased. The respiratory mechanism in slices of brain cortex from 1‐day‐old rats was much less affected by anoxia and sensitivity to anoxia develops with age.
METABOLISM OF PHOSPHATIDYLCHOLINE, PHOSPHATIDYLINOSITOL AND PALMITYL CARNITINE IN SYNAPTOSOMES FROM RAT BRAIN1
Authors: Abdel‐Latif A. A. , Roberts M. B. , Karp W. B. , Smith J. P.
Published: December 2006

Abstract— Synthesis of phosphatidylcholine, phosphatidylinositol and palmityl carnitine in synaptosomes isolated from rat brain was investigated and compared with the synthesis of these compounds in microsomes and mitochondria. Electron microscopic and marker enzyme studies showed the contaminants in the synaptosomal preparation to consist of a few microsomes and almost no free mitochondria. In synaptosomes, addition of 1,2‐diglyceride exerted no effect on the incorporation of [14C]choline into phosphatidylcholine or on the incorporation of [3H]myo‐inositol into phosphatidylinositol, but it stimulated the incorporation of CDP[1,2‐14C]choline into phosphatidylcholine by more than 50 per cent. The incorporation of the latter in intact synaptosomes, lysed synaptosomes and purified mitochondria was 15‐6, 27 and 9‐9 per cent, respectively, of that in the microsomes. The incorporation of [3H]myo‐inositol into the phosphatidylinositol of synaptosomes and purified mitochondria was 15‐8 and 11‐1 per cent, respectively, of that in the microsomes. Maximal incorporation of [3H]myo‐inositol occurred at pH 7–5 in a medium containing Mg2+ and CTP; it was linear with time and protein concentration and was inhibited by 1 mM Ca2 + but unaffected by the presence of ATP. This incorporation of myo‐inositol appeared to occur through the reversal of the CDP‐diglyceride: inositol transferase reaction. The demonstration of carnitine palmityl transferase in synaptosomes indicated that, as in mitochondrial and erythrocyte membranes, fatty acids can be transported across the synaptosomal membrane. In contrast to mitochondria where maximal incorporation of [14C]carnitine into palmityl carnitine was observed after 20 min of incubation, the incorporation in synaptosomes increased as a function of time up to 60 min of incubation.

We conclude that synaptosomes can carry on de novo synthesis of lipids, although at a limited rate. From the present data we cannot state with certainty how much of this synthesis is attributable to membranes originating from the endoplasmic reticulum.
INTERSPECIES CORRELATIONS OF CEREBRAL CORTICAL OXYGEN CONSUMPTION, ACETYLCHOLINESTERASE ACTIVITY AND CHLORIDE CONTENT: STUDIES ON THE BRAINS OF THE FIN WHALE (BAAENOPTERA PHYSALUS) AND THE SPERM WHALE (PHYSETER CATODON)
Authors: Tower D. B. , Young O. M.
Published: December 2006

Abstract— Previously reported interspecies correlations of cerebral cortical oxygen consumption (as a function of average species body weight) and of cerebral cortical chloride content and acetylcholinesterase activity (as functions of average species brain weight) were confirmed by selected repetitions of the determinations and were further validated by inclusion of data from samples of cerebral cortex of the fin whale (Balaenoptera physalus) and the sperm whale (Physeter catodon). Despite the fact that the samples of whale brain were obtained at 15–22 h after death and were preserved only by simply freezing on dry ice, no evidence of significant postmortem autolysis was obtained by examination of gangliosides, myelin basic proteins, acidic and amide residues of total isolated proteins, and lipid composition of cerebral cortical samples. The chloride content of whale cerebral cortex was 65.1 (± 12) μequiv./g, and the activity of acetylcholinesterase was 0.78 (± 0.28) μmol of acetylthiocholine hydrolysed min‐1 g‐1, with no differences in these values between the two species. The two interspecies correlations yielded regression curves with calculated slopes for chloride of +9.07 (± 0.37) and for acetylcholinesterase of ‐0–204 (± 0.006), each correlating significantly as functions of species brain weight at P < 0.001. Under optimal conditions of slow freezing and thawing of cerebral cortical slices equilibrated with 15 % (v/v) glycerol, oxygen consumption by the slices was only 50 per cent of the rate exhibited by fresh (unfrozen) slices. Despite the suboptimal conditions of freezing and thawing of the large (> 200 g) samples of whale (and beef) brain, subsequently prepared slices of whale cerebral cortex respired at a rate of 20.6 (± 1.8) μmol of O2 taken up h‐1 g‐1, also 50 per cent of the value of 40.7 predicted by extrapolation for fresh (unfrozen) slices. When plotted as a function of species body weight, the data for oxygen consumption by previously frozen cortical slices paralleled the regression curve for fresh slices previously characterized by the expression, R = 5.4 W‐0.1. The data obtained for the two species of great whales (brain weights, 6800–7800 g; body weights, 3–53 ± 104 kg) served to ‘anchor’ with more certainty the upper limits of the three interspecies correlations re‐examined here and thus provided a better basis for predicting by extrapolation normal values for human cerebral cortex.
THE PATTERNS OF ARYLSULPHATASES A AND B IN HUMAN NORMAL AND METACHROMATIC LEUCODYSTROPHY TISSUES AND THEIR RELATIONSHIP TO THE CEREBROSIDE SULPHATASE ACTIVITY
Authors: Harzer K. , Stinshoff K. , Mraz W. , Jatzkewitz H.
Published: December 2006

Abstract— The arylsulphatase A and B patterns of human tissues and leucocytes have been established by isoelectric focussing. Assay conditions, which enable an evaluation of these patterns as quantitatively as possible, have been studied. The dependences of the enzyme patterns on the origin of the tissues and on the storage conditions have been determined. The arylsulphatase A obtained by isoelectric focussing exhibits cerebroside sulphatase activity in the presence of detergents. A purified preparation of the arylsulphatase B likewise shows a significant, although low, cerebroside sulphatase activity. In cases of the conventional types of metachromatic leucodystrophy the arylsulphatase A activity is missing, while in an atypical form of this disease (‘ML Variant’ according to Austinet al. (1965) the arylsulphatase A, B and C activities are deficient. In both forms, however, residual activities of the deficient enzymes could be detected which showed isoelectric points identical to those of the normal enzymes.

The following nomenclature is proposed: ‘Variant B’ for the conventional type, in which the arylsulphatase B activity is present, and ‘Variant O’ for the exceptional cases, in which all arylsulphatase activities are deficient. The significance of the cerebroside sulphatase activity of arylsulphatase B for a possible residual turnover of cerebroside sulphates in the conventional type of the disease is discussed.
COMPETITION HYBRIDIZATION STUDIES ON BRAIN RTBONUCLEIC ACID FROM RATS REARED IN ENRICHED AND DEPRIVED ENVIRONMENTS
Authors: Mushynski W. E. , Levitan I. B. , Ralwrez G.
Published: December 2006

Abstract— Male rats of the Sprague‐Dawley strain were weaned at 21–23 days of age and littermates were assigned to enriched or deprived environments. At days 7, 20 and 35 following separation of littermates, the brain RNA from 3 out of each group of 12 enriched or deprived rats was pulse‐labelled with [5‐3H]uridine, while the remaining rats in each group were used as a source of unlabelled competitor RNA. The RNA was used in DNA:RNA hybridization studies involving simultaneous competition between labelled RNA and varying amounts of unlabelled competitor RNA from the brains of enriched or deprived rats. The number of groups of enriched and deprived rats studied was 2 each at day 7 and at day 20, while 3 groups were employed at the 35‐day interval. No significant qualitative differences were found between RNA from the brains of enriched and deprived rats.
PROPERTIES AND LOCALIZATION OF BICARBONATE‐STIMULATED ATPase ACTIVITY IN RAT BRAIN1
Authors: Kimelberg H. K. , Bourke R. S.
Published: December 2006

Abstract— A 20–30 per cent stimulation of ATPase activity by added NaHCO3 was found in homogenates of a variety of mammalian tissues. The subcellular distribution of this (HCO3‐)—stimulated activity was examined in detail using rat cerebral cortex. The stimulation was specific for the HCO3‐ ion and was predominantly localized in the mitochondrial subcellular fraction, in which a 2‐fold stimulation by HCO3‐ was found. The effect of inhibitors supported the identification as the mitochondrial ATPase. Both sodium azide and thiocyanate were inhibitory. The effects of varying the Mg2+ concentration, HCO3‐ concentration, and pH were also studied. In the presence of HCO3‐ the Km for ATP was reduced approximately 3‐fold. There was no effect of HCO3‐ on the ma + K) ATPase or Mg2+ ATPase from the microsomal fraction of rat cerebral cortex. Our findings have been discussed in relation to previous work on HCO3‐ stimulation of ATPae activity in subcellular fractions from other tissues, as well as its possible relevance to the known effects of HCO3‐ and carbonic anhydrase on active ion transport.
EFFECTS OF ADDED SUBSTANCES ON RNA AND PROTEIN SYNTHESIS IN IMMATURE NEURONS
Authors: Hemminki Kari
Published: December 2006

Abstract— A newly described method for the isolation of morphologically intact neurons from newborn rat brain was used to study the influence of inhibitors and neuroactive substances on RNA and protein synthesis in these cells in vitro. Incorporation of [14C]‐uridine into RNA and [3H]leucine into protein proceeded rapidly and continued up to 3 h. When the incorporation mixture was chased at 20 min with an excess of nonradioactive uridine and leucine, hardly any degradation of labelled RNA was noted during the following 2 h 40 min. In contrast, the specific radioactivity of proteins decreased by 22 per cent indicating turnover of cellular proteins.

Incorporation of labelled leucine into protein was markedly inhibited in the presence of NaF and cycloheximide but not affected in the presence of chloramphenicol or pancreatic RNase. A mixture of ATP + GTP depressed the incorporation by 38 per cent. The responses to ATP + GTP and RNase indicated that the incorporation system was typically cellular. Acetylcholine, γ‐aminobutyrate, noradrenaline and phenylalanine in the incubation medium depressed the incorporation of labelled uridine into RNA by 10–30 per cent and 5‐hydroxytryptamine by 75 per cent. Acetylcholine, γ‐aminobutyrate and noradrenaline had no effect on protein synthesis, while 5‐hydroxytryptamine and phenylalanine inhibited the incorporation by 60–80 per cent. Testosterone and prednisolone depressed both RNA and protein synthesis while thyroxine caused slight but non‐significant stimulation.
PRE‐ AND POSTSYNAPTIC UTILIZATION OF ATP AND CREATINE PHOSPHATE AT THE NERVE‐ELECTROPLAQUE JUNCTION
Authors: Chmouliovsky M. , Dunant Y. , Hojvat S.
Published: December 2006

Abstract— When the electric organ of the Torpedo fish was stimulated in vivo and in vitro, there was a large rapid breakdown of creatine phosphate (CrP), and a slower decrease in the level of ATP. The acetylcholine content showed a parallel fall to that of ATP. Curare was used to interrupt synaptic transmission, allowing the presynaptic nerve endings to remain sensitive to stimulation, but simultaneously keeping electroplaques inactive. In stimulated curarized tissue, the level of ATP was not changed, while the breakdown of CrP was still 25% of that observed in non‐curarized controls. These observations suggest that presynaptic nerve endings, despite their small size, utilize a very high amount of energy.
THE INHIBITION OF RAT BRAIN ATP: CITRATE OXALOACETATE‐LYASE BY L‐GLUTAMATE1
Authors: Szutowicz A. , Stepie M. , Angielski S.
Published: December 2006

Abstract—

Among 16 amino acids tested only D‐ and L‐glutamate were found to be specific inhibitors of citrate lyase from adult rat brain. Glutamate also inhibited citrate lyase from the liver of starved animals while it was without effect on lyase from those refed with carbohydrate. L‐Glutamate did not inhibit the citrate lyase from brains of newborn rats.

The inhibitory effect of L‐glutamate was increased when the time of preincubation was prolonged, but only in the presence of both ATP and MgCl2. This time‐dependent inhibition could be reversed by addition of high concentrations of ATP.

L‐Glutamate was without effect on Km and Vmax values for MgCl2. Excess of Mg2+ ions was indispensable for glutamate inhibition.

L‐Glutamate was shown to be competitive with respect to the ATP inhibitor of the lyase, with a Ki of 0.3mM.

The mechanism of L‐glutamate inhibition may be due to the reaction of a glutamate‐Mg complex with the phosphorylated intermediary form of the lyase, resulting in the formation of a lyase‐glutamate complex.

The physiological significance of the inhibitory action of glutamate is discussed.
POSTNATAL CHANGES IN THE HIGH AFFINITY UPTAKE OF GLYCINE and GABA IN THE RAT CENTRAL NERVOUS SYSTEM
Authors: Johnston G. A. R. , Davies L. P.
Published: December 2006

Abstract— High affinity uptake systems for GABA into slices of cerebral cortex and for glycine into slices of spinal cord have been demonstrated in rats of 1 and 10 days postnatal age and compared with the systems in tissue slices from adult rats. For both systems there was an increase in the maximal rate of uptake of the substrate with development. For glycine uptake there was no significant change in apparent Km during development, whereas there was a four‐fold increase in the apparent Km for GABA uptake. There were some changes with development in the apparent substrate specificity of the two systems suggesting increased specificity with maturation. Bicuculline and strychnine, antagonists of the postsynaptic inhibitory actions of GABA and glycine, produced convulsions in 1‐, 2‐ and 10‐day‐old rats following intraperitoneal injection of doses somewhat lower than those required to convulse adult rats. These findings are consistent with other evidence that glycine and GABA are functioning as inhibitory transmitters at least as soon as 1 day after birth.
POSTNATAL CHANGES IN THE LEVELS OF GLYCINE AND THE ACTIVITIES OF SERINE HYDROXYMETHYLTRANSFERASE AND GLYCINE: 2‐OXOGLUTARATE AMINOTRANSFERASE IN THE RAT CENTRAL NERVOUS SYSTEM
Authors: Davies L. P. , Johnston A. R.
Published: December 2006

Abstract— Of the amino acids found in the CNS of 10‐day‐old rats the concentration of glycine alone was significantly higher in the spinal cord than in all other regions. Spinal levels of glycine, cystathionine, isoleucine and lysine from 1‐ and 10‐day‐old rats did not differ significantly from adult values, whereas the levels of most other amino acids, including GABA, glutamate, glutamine and taurine, were higher in the young animals than in the adults. Aspartate was the only amino acid found in lower concentration in the spinal cord of young animals than in adult animals. These and other observations support the conclusion that glycine is used as an inhibitory transmitter in rat spinal cord early in postnatal life. There was a general decrease in the activity of serine hydroxymethyltransferase and a slight increase in the activity of glycine:2‐oxoglutarate aminotransferase in the CNS during development. The activity of neither enzyme correlated on a regional basis with the glycine content. The high level of hydroxymethyltransferase activity in the cerebellum of 10‐day‐old rats suggests that the activity of this enzyme reflects cell growth rate.
GLYCOPROTEINS IN BRAIN TISSUE OF THE O‐VARIANT OF GM2 GANGLIOSIDOSIS
Authors: Brunngraber E. G. , Brown Barbara D. , Aro Aurelia
Published: December 2006

Abstract— The dialysableglycopeptide preparation recovered from the glycoproteins in cerebral gray matter of a case of the O‐variant form of GM2 gangliosidosis contained four fold more N‐acetylglucosamine and mannose than a similar preparation from normal gray matter. In the O‐variant form of GM2 gangliosidosis, the enzymes β‐N‐acetylhexosaminidases A and B are missing. A three‐ and four‐fold elevation, respectively, of N‐acetylglucosamine and mannose in the dialysable glycopeptide preparation from a case of Tay‐Sachs disease (B‐variant form of GM2 gangliosidosis) was noted. The B‐variant lacks hexosaminidase A but has ample supplies of hexosaminidase B. The brain level of glycosaminoglycans was not affected in the O‐ and B‐variant forms of GM2 gangliosidosis.
CHANGES IN THE ACETYLCHOLINE CONTENT OF DIFFERENT BRAIN REGIONS OF THE RAT DURING A LEARNING EXPERIMENT1
Authors: Matthies H. , Rauca Ch. , Liebmann H.
Published: December 2006

Abstract— The ACh content of the rat hippocampus, visual cortex, auditory cortex and corpus striatum was estimated as so‐called free, labile‐bound and stable bound acetylcholine at different times after the learning of a brightness discrimination.

In the hippocampal region the free acetylcholine was highly increased immediately after the training, whereas the stable bound ACh and the labile‐bound fraction rose 70 min and 4 h respectively‐after completion of training.

Only small alterations of the ACh fractions were observed in the visual and auditory cortices. In the corpus striatum no changes appeared.
ISOLATION OF HYDROPHOBIC PROTEINS BINDING NEUROTRANSMITTER AMINOACIDS. GLUTAMATE RECEPTOR OF THE SHRIMP MUSCLE
Authors: de Plazas Sara Fiszer , Robertis E. De
Published: December 2006

Abstract— –Muscle of shrimps (Artemisia longinaris) were extracted with chloroform‐methanol (2:1, v/v) and the proteolipids were separated by column chromatography on Sephadex LH‐20. Three peaks of protein were eluted with chloroform and one with chloroform‐methanol (4:1, v/v). Only the first peak eluted between 16 and 26 ml of chloroform showed binding for l‐(14C]‐glutamate. The type of saturation curve obtained suggests the existence of single type of binding site. The saturation is reached at one mole of l‐glutamate per 320,000 g protein and the purification achieved about 3200‐fold. The protein binding‐glutamate does not bind GABA, aspartate or glutamine. The binding of l‐[14C]‐glutamate was inhibited by dl‐α ‐methyl glutamic acid and l‐glutamic acid diethyl ester. The binding properties of this hydrophobic protein fraction suggest that it may represent the isolated glutamate receptor of the shrimp muscle.
FREE FATTY ACIDS, DIACYL‐ AND TRIACYLGLYCEROLS AND TOTAL PHOSPHOLIPIDS IN VERTEBRATE RETINA: COMPARISON WITH BRAIN, CHOROID AND PLASMA12
Authors: Aveldanto Marta I. , Bazaan N. G.
Published: December 2006

Abstract— A comparative study of the concentration and fatty acid distribution in diacyl‐ and triacylgly‐cerols. free fatty acids and total phospholipids from rabbit, cattle and toad retina is presented. With respect to the toad, a comparison is made with brain, choroid and plasma lipids. Marked differences in diacylglycerol composition and levels between mammalian and toad retina are found: in the mammal arachidonate predominates (25 per cent), in the toad docosahexaenoate is the main fatty acid (42 per cent). The total phospholipid composition parallels that of the diacylglycerols only in the toad, whereas in the mammalian retina the phospholipids are richer in docosahexaenoate than are the diacylglycerols. It is suggested that there is a relationship between diacylglycerols and phosphoglyceride metabolism in the toad; in the retinas of other species the diacylglycerols may be related to specific phosphatides. In the three species, triacylglycerols show high levels of unsaturation; however, marked differences are found in the distribution of polyunsaturated acyl groups: in the cattle and toad retina docosahexaenoate predominates. whereas in the rabbit a higher proportion of 22:4 is found. Retina free fatty acid pools also show different features in the three species: the cattle retina contains the highest proportion of free 20:4 and 22:6. The triacylglycerol concentration is much higher in the toad choroid than in the retina, although the fatty acid compositions are similar. A possible relationship between these choroid lipids and those of the retina is suggested.
UNEQUAL PATTERNS OF DEVELOPMENT OF SUCCINATE‐DEHYDROGENASE and ACETYLCHOLINESTERASE IN PURKINJE CELL BODIES and GRANULE CELLS ISOLATED IN BULK FROM THE CEREBELLAR CORTEX OF THE IMMATURE RAT1
Authors: Sellinger O. Z. , Legrand J. , Clos J. , Ohlsson W. G.
Published: December 2006

Abstract— –A preparative procedure for the isolation in bulk of two cellular populations of the cerebellar cortex of the immature rat, the granule cells and the Purkinje cell bodies, is described. The procedure is used to delineate the developmental pattern of succinate‐INT‐reduclase (EC 1.3.99.1) and acetylcholinesterase (EC 3.1.1.7) in the crucial period of cerebellar maturation, i.e. between 12 and 19 days postnatally. Although the overall yield of neuronal RNA diminished with age, the proportion of RNA in the Purkinje cell body fraction increased while that in the granule cells decreased and microscopic examination of the fractions confirmed this result. The yields of succinate‐INT‐reductase and of acetylcholinesterase in the fractions paralleled the yields of RNA. A significant finding was the trend toward diminishing specific activities (units/μg of RNA) with age of both enzymes in the Purkinje cell bodies as against the opposite, upward trend of their specific activities in the granule cells. An additional finding of interest was the different ratio of true acetylcholinesterase/total cholinesterase activity in the two cell types, with the granule cells consistently exhibiting higher true acetylcholinesterase values than the Purkinje cell bodies. The present report thus supplements the histoenzymological data on the developing rat cerebellum in that it reveals specific differences in the enzymatic development of two different cerebellar types, a finding which was greatly facilitated by the availability of the procedure for their bulk isolation.
PROPERTIES AND FUNCTION OF THE CALCIUM‐DEPENDENT INCORPORATION OF CHOLINE, ETHANOLAMINE AND SERINE INTO THE PHOSPHOLIPIDS OF ISOLATED RAT BRAIN MICROSOMES1
Authors: Gain. A. , Di Midio G. E. , Brunetti M. , Amaducci L. , Porcellati G.
Published: December 2006

Abstract— The calcium‐dependent incorporation of choline, ethanolamine and L‐serine into the phospholipids of isolated rat brain microsomes has been studied in vitro, and various properties of the incorporation have have been examined. The optimum pH for the incorporation of each base was found to vary inversely with the Ca2‐ concentration. Conversely, the optimal Ca2 + concentration for the exchange of the bases increased with decreasing pH values. The enzymic system for the incorporation of ethanolamine appeared to be saturated by two substrate concentrations, i.e. 0‐2 and 1‐7‐2‐0 mM. At low ethanolamine concentration (0‐2 mM] much less incorporation of the base occurred into the alkenylacyl‐ and alkylacyl‐derivatives of ethanolamine phosphoglycerides compared to that into the diacyl species, whereas the difference becomes smaller at a high substrate concentration (1‐7 mM). At pH 81 and 2 mM‐Ca2+ the apparent Km of ethanolamine at low substrate concentration was 80 × 10‐5 M, and this value increased to 16‐2 × 10‐4.viat 10mM‐Ca2+ concentration. At similar pH the Km values for choline and L‐serine were 5.88 × 10‐4M and 40 × 10‐4 M at 2 mM‐ and 10mM‐Ca2 + concentrations, respectively. The properties of the enzyme system show differences for the three substrates when various factors are changed during incubation. These and other results indicate that more than one enzyme is probably involved in the Ca2+‐medialed exchange of nitrogenous bases.
ENZYMIC STUDIES OF SULPHATASES IN TISSUES OF THE NORMAL HUMAN AND IN METACHROMATIC LEUKODYSTROPHY WITH MULTIPLE SULPHATASE DEFICIENCIES: ARYLSULPHATASES A, B AND C, CEREBROSIDE SULPHATASE, PSYCHOSINE SULPHATASE AND STEROID SULPHATASES1
Authors: Eto Y. , Rampini S. , Wiesmann U. , Herschkowitz N. N.
Published: December 2006

Abstract— Several sulphatases (arylsulphatases A, B and C, cholesterol sulphatase, dehydroepiandroster‐one sulphatase, cerebroside sulphatase and psychosine sulphatase) were deficient in various tissues from two patients with a variant form of metachromatic leukodystrophy. Deficient activities of cerebroside sulphatase and psychosine sulphatase, using physiological substrates, in tissues from metachromatic leukodystrophy with multiple sulphatase deficiencies provided another example that these enzymes may be identical to arylsulphatase A. β‐Galactosidase activity was reduced to about 30‐50 per cent of normal in brain and liver. Other lysosomal enzyme activities were found to be normal or elevated five to eight times. Arylsulphatase B isolated from the liver of one patient was abnormal, with respect to pi (70) and enzyme kinetics. In mixing experiments with normal enzymes the reduced activities of arylsulphatases A. B and C, cerebroside sulphatase and steroid sulphatases were shown not to be due to the presence of endogenous inhibitors. No arylsulphatase A or B activity in the brain specimen from the patient with multiple sulphatase deficiencies could be detected on isoelectric focussing. In normal brain tissue arylsulphatase A had a pi of 4‐6‐4‐8 while arylsulphatase B had a pi of 7‐8 and 8‐1. When 4‐methylumbelliferyl sulphate was used as a substrate the elution patterns of normal brain and liver arylsulphatase B were more heterogeneous and showed more variation than that when p‐nitrocatechol sulphate was used. Arylsulphatase C and steroid sulphatases (cholesterol sulphatase, dehydroepiandrosterone sulphatase and oes‐trone sulphatase I were solubilized by the addition of lysolecithin and Triton X‐100 and subjected to isoelectric focussing. The pi of cholesterol sulphatase, oestrone sulphatase and arylsulphatase C was 6‐8, and the elution patterns of the activities of these enzymes were similar. The pattern of dehydroepiandrosterone sulphatase was more heterogeneous and two major peaks were observed at pi 6 5 and 70. Residual enzyme activities of arylsulphatase C and steroid sulphatases from the brain of the patient with multiple sulphatase activities were not detectable by isoelectric focussing. Simultaneous deficiencies of arylsulphatase C and steroid sulphatases plus isoelectric focussing findings in tissues suggest that these enzymes are closely related in regard to their function. The nature of the genetic defect in metachromatic leukodystrophy with multiple sulphatase deficiencies is discussed.
EFFECTS OF LESIONS AND DRUGS ON BRAIN TRYPTAMINE
Authors: Marsden C. A. , Curzon G.
Published: December 2006

Abstract— The effects of various drugs and lesions on rat brain 5‐hydroxytryptamine and tryptamine were determined. Monoamine oxidase inhibition caused a proportionately greater increase in tryptamine than in 5‐hydroxytryptamine, reserpine depleted 5‐hydroxytryptamine but had no effect on tryptamine while p‐chlorophenylalanine lowered 5‐hydroxytryptamine but increased tryptamine. α‐Methyl‐p‐tyrosine reduced striatal dopamine with no effect on either 5‐hydroxytryptamine or tryptamine. Increasing brain tryptophan by amphetamine administration. 24 h food deprivation or giving L‐tryptophan did not increase brain tryptamine. However a high dose of L‐tryptophan (100 or 200mg/kg) together with a monoamine oxidase inhibitor caused a proportionately much greater increase in tryptamine than in 5‐hydroxytryptamine. Raphe lesions reduced 5‐hydroxytryptamine by 64 per cent and tryptamine by only 29 per cent while intraventricular 6‐hydroxydopamine lowered striatal dopamine (56 per cent), had no effect on 5‐hydroxytryptamine but reduced tryptamine by 24 per cent, suggesting that tryptamine can be formed in both 5‐HT and catecholaminergic neurones.

The results are discussed in relation to the formation, distribution, storage and possible transmitter function of tryptamine in rat brain.
L‐GLUTAMIC ACID DECARBOXYLASE IN NON‐NEURAL TISSUES OF THE MOUSE
Authors: Drummond R. J. , Phillips A. T.
Published: December 2006

Abstract— Low levels of γ‐aminobutyric acid (GABA) and of glutamic acid decarboxylase (GAD) activity have been detected in mouse kidney, liver, spleen and pancreas. Quantitation of both 14CO2 and [14C]GABA produced in radiometric assays from [U‐14CJglutamic acid has shown that measurement of 14CO2 evolution alone is not, in all cases, a valid estimate of true GAD activity. As evidenced by increased ,14CO2 production upon addition of NAD and CoA to assay mixtures, radiometric assay of GAD activity in crude homogenates may yield 14CO2 via the coupled reactions of glutamic acid dehydrogenase and a‐ketoglutarate dehydrogenase. The addition of 1 mM aminooxyacetic acid (AOAA) to assays of kidney homogenates inhibited [,14C]GABA production 92 per cent while 14CO2 production was inhibited only 53 per cent. No evidence was found to confirm the reported existence of a second form of the enzyme, GAD II. previously described by Haber el al. (Haber B., Kuriyama K. & Roberts E. (1970) Biochem. Pharmac. 19, 1119‐1136). Based on sensitivity‐to AOAA and chloride inhibition, the GAD activity in mouse kidney is. apparently, indistinguishable from that of neural origin.
THE EFFECT OF DIFFERENT DIETARY LEVELS OF ESSENTIAL FATTY ACIDS ON LIPIDS OF RAT CEREBRUM DURING MATURATION1
Authors: Alling C. , Bruce Å. , Karlsson I. , Svennerholm L.
Published: December 2006

Abstract— Three dietary levels of essential fatty acids, 30, 0‐75 and 007 calorie‐%, with a linoleic: linolenic acid ratio of 4:1, were fed to rats for two generations. In the third generation the weight of the cerebrum and the concentration of its lipids and the fatty acid composition of phosphoglycerides were determined from term to 120 days of age. The cerebral weights and the concentrations of phospholipids, cholesterol and cerebrosides differed only slightly between the three dietary groups. The accretion of fatty acids of the linoleic acid series was independent of the dietary essential fatty acid level while the accretion of fatty acids of the linolenic acid series was markedly reduced in the groups with low essential fatty acid supply. The sum of the total polyunsaturated fatty acids in ethanolamine phosphoglycerides differed only slightly between the groups. The proportion of the major polyunsaturated fatty acid of the linoleic acid series was equal between the groups while that of 22:6 (n‐3) was much lower in the groups fed 007 calorie % essential fatty acids. In these latter groups the relative concentrations of 22:5 (n‐6), 20:3 (n‐9) and 22:3 (n‐9) were increased. The differences in the fatty acid composition were dependent on the age of the rats. They were largest in newborn rats and diminished with age after weaning.
THE EFFECT OF HYPERBARIC OXYGENATION ON THE LEVELS OF 5‐HYDROXYTRYPTAMINE, NORADRENALINE, DOPAMINE AND FREE AMINO ACIDS IN WHOLE MOUSE BRAIN
Authors: Huggins A. K. , Nelson D. R.
Published: December 2006

Abstract— The effect of hyperbaric oxygenation on the levels of monoamines and free amino acids in whole mouse brain were found to vary with time of exposure and the pressure system used. Depression of 5‐hydroxytryptamine (5‐HT), noradrenaline (NA) and dopamine (DA) levels occurred after 40‐60 min in 100% oxygen at atmospheric pressure. These effects occurred more rapidly at higher pressures but had disappeared by about 20 min. No significant change in free glutamic acid, glycine, tryptophan, tyrosine or taurine levels was observed following exposure for up to 60 min in oxygen at 4 atm. A progressive decrease in alanine occurred when oxygen replaced air and the pressure and exposure time increased. Other changes, detected in post‐convulsant mice only, were increases in the leucine and valine pools. The relationship of these results to other work is discussed.
CHARACTERIZATION OF A DOPAMINE‐SENSITIVE ADENYLATE CYCLASE IN THE RAT CAUDATE NUCLEUS
Authors: Clement‐Cormier Yvonne C. , Parrish R. G. , Petzold G. L. , Kebabian J. W. , Greengard P.
Published: December 2006

Abstract— An adenylate cyclase present in the caudate nucleus of rat brain, which is selectively stimulated by low concentrations of dopamine, and which is believed to mediate dopaminergic synaptic transmission, has been characterized with respect to several properties. The parameters studied included temperature, pH, ATP concentration, Mg/ATP ratio, and metal ion specificity. The effects of other compounds, including EGTA, NaF and several guanosine nucleotides, were also tested on the dopa‐mine‐sensitive adenylate cyclase. In addition, the subcellular distribution of the enzyme was studied. The highest specific activity was found in subcellular fractions enriched in nerve endings. A half‐maximal increase in the activity of the enzyme in a subcellular fraction occurred in the presence of 4 × 10−6 M dopamine. Fluphenazine, a dopamine antagonist, competitively inhibited the activity of the enzyme in this fraction, with a calculated inhibition constant (Ki) of 8 × 10−9M.
UPTAKE OF GLUCOSE ANALOGUES BY RAT BRAIN CORTEX SLICES: A KINETIC ANALYSIS BASED UPON A MODEL
Authors: Lund‐Andersen H. , Kjeldsen Christel S.
Published: December 2006

Abstract— In slice preparations the exchange of dissolved substances between cells and incubation medium is delayed by diffusion through the extracellular space. The delay may seriously interfere with the study of membrane transport in terms of unidirectional fluxes across the cell membranes. A three‐compartment serial model has been developed to describe exchange between slice and incubation medium. By aid of this model it is shown that the diffusion delay prevents determination of unidirectional fluxes for the two non‐metabolizable glucose analogues 3‐O‐methylglucose and α‐methyl‐glucosidc. The membrane transport of the slowly transported α‐methylglucoside can however be examined by aid of the model whereas the transport of 3‐O‐methylglucose is so rapid that it can not be examined with respect to Vmax Km and Kr. An attempt to determine these parameters will result in falsely large values which reflect extracellular diffusion and not membrane transport.
ACTIVITIES OF SOME ENZYMES INVOLVED IN HOMOCYSTEINE METHYLATION IN BRAIN, LIVER AND KIDNEY OF THE DEVELOPING RHESUS MONKEY
Authors: Sturman J. A. , Gaull G. E. , Niemann W. H.
Published: December 2006

Abstract— The specific activities of the enzymes responsible for remethylation of homocysteine to methionine. N5‐methyltetrahydrofolate‐homocysteine methyltransferase and betaine‐homocysteine methyl‐transferase, and of the enzyme responsible for transferring the β‐carbon atom of serine to tetrahydrofolate. serine tetrahydrofolate 5,10‐hydroxymethyltransferase, have been measured in brain, liver and kidney of the developing Rhesus monkey from mid‐gestation, from birth and neonatal life to maturity. The specific activity of N5‐methyltetrahydrofolate‐homocysteine methyltransferase in all tissues is higher during late gestation and shortly after birth than it is in the adult, and in brain and liver it shows a positive correlation with increasing gestational age. Betaine‐homocysteine methyltransferase activity is not measurable in brain. In liver it increases linearly during fetal and neonatal development until values found in the adult are reached. In kidney there is a sharp linear increase during the period of gestation studied. The drop at birth is followed by a sharp increase back to values noted at the end of gestation and thereafter a slow increase to values found in the adult. The specific activity of serine‐tetrahydrofolate 5,10‐hydroxymethyltransferase tends to be higher in fetal and early neonatal brain than it is in adult brain, whereas in liver and kidney it is low in the fetus and rises during development to reach values found in the adult some months after birth.
EFFECTS OF AMPHETAMINE ADMINISTRATION IN VIVO ON IN VITRO PROTEIN SYNTHESIZING SYSTEM FROM RAT BRAIN 1
Authors: Widelitz Martin M. , Coryell Marlene R. , Widelitz Howard , Avadhani Narayan G.
Published: December 2006

Abstract— A highly active in vitro protein synthesizing system (S‐28) has been prepared from rat brain. Poly (U)‐dependent [3H] phenylalanine incorporation by brain S‐28 system is significantly inhibited by D‐amphetamine. The extent of inhibition by amphetamine is significantly higher than by other biogenic amines such as dopamine and serotonin. At the 100°g level of amphetamine, the inhibition is about 70°. Experiments with ribosomes and soluble enzymes from control and amphetamine‐treated systems indicate that the observed inhibition may be due to the effect of the drug on the ribosomes. Kinetic analysis of the reaction mixture in the presence as well as absence of D‐amphetamine indicate that this sympathomimetic drug inhibits polysome formation in vitro.
ESTIMATION OF NORADRENALINE AND ITS MAJOR METABOLITES SYNTHESIZED FROM [3H]TYROSINE IN THE RAT BRAIN
Authors: Nielsen M
Published: December 2006

Abstract— A new procedure is described for the estimation of [3H]noradrenaline (NA) and its major metabolites free and conjugated 3‐methoxy‐4‐hydroxyphenylglycol (MOPEG) and free and conjugated 3,4‐dihydroxyphenylglycol (DOPEGI in the rat brain. The procedure involves adsorption on to alumina, cation exchange chromatography. enzymatic hydrolysis of conjugates and thin‐layer‐chromatography after intraventricular (IVT) or intravenous injection of [3H]tyrosine. In a time‐course study the formation and accumulation of the metabolites have been measured from 15min to 23h after IVT injection of [3H]tyrosine. [3H]MOPEG and [3H]DOPEG were found in almost equal amounts during the synthesis phase of [3H]NA as well as during the storage and disappearance phase of [3H]NA.

The maximum levels of conjugated [3H]MOPEG and conjugated [3H]DOPEG were found 2 h after IVT [3H]tyrosine. At this time interval the levels of free [3H]MOPEG and free [3H]DOPEG amounted to 25% and 11%, respectively of the corresponding conjugates. Increasing doses of IVT injected [3H]tyrosine (10‐90 °Ci) revealed that the accumulation of [3H]NA and metabolites was linear up to about 50 °Ci. Following intravenous instead of IVT injection of [3H]tyrosine. much higher doses (325 °Ci) were needed to obtain measurable amounts of total [3H]MOPEG and [3H]DOPEG‐SO4 in the rat brain.

The formation of labelled NA metabolites from [3H]NA in the rat brain in vim measured as total [3H]MOPEG and [3H]DOPEG‐SO4 was influenced by drugs affecting [3H]NA synthesis, release and metabolism. Synthesis inhibition with a‐methyltyrosine (250mg‐kg−1) or FLA‐63 (30mg‐kg−1) and inhibition of monoamine oxidase with pargyline (75mg‐kg−1) or clorgyline (2mg‐kg−1) strongly decreased the accumulation of total [3H]MOPEG and [3H]DOPEG‐SO4. Noradrenaline receptor blockade with phenoxybenzamine (20mg‐kg−1) increased both total [3H]MOPEG and [3H]DOPEG‐SO4 to about 160% of the control values. NA release and uptake inhibition induced by d‐amphetamine (10mg‐k−1) or phenylethylamine (two doses of 80mg‐kg−1) decrease strongly the levels of [3H]NA and [3H]DOPEG‐SO4. whereas total [3H]MOPEG was only very slightly decreased or even increased as compared to controls.
REGIONAL BRAIN INDOLEAMINE METABOLISM FOLLOWING CHRONIC PORTACAVAL ANASTOMOSIS IN THE RAT
Authors: Cummings M. G. , Sotters P. B. , James J. H. , Keane Jane M. , Fischer J. E.
Published: December 2006

Abstract— Four weeks after portacaval anastomosis in the rat. a profound change in the pattern of the plasma neutral ammo acids occurred. These changes were accompanied by marked regional changes in brain trvptophan. 5‐HT (5‐hydroxytryptamine) and 5‐HIAA (5‐hydroxyindoleacetic acid). Tryptophan was elevated in all the regions studied as was 5‐HIAA. 5‐Hydroxytryptamine was significantly elevated only in midbrain and medulla pons. A small but significant increase in free trvptophan concentration in plasma was seen in rats following portacaval anastomosis, but this elevation was insufficient in magnitude to account for thc changes in brain trvptophan. Administration of a solution containing equimolar concentrations of the three branched‐chain amino acids, leucine. isoleucine and valine. caused a decrease in brain indoles towards normal levels. These results suggest that the altered plasma neutral amino acid pattern which accompanies portacaval anastomosis and its effect on competitive amino acid transport across the blood brain barrier is an important factor contributing to the raised levels of indoles in brain under these circumstances. The relationship of these results to the recently reported use of amino acid infusions in the treatment of hepatic encephalopathy is discussed.
THE UPTAKE OF [3H]CHOLINE BY SNAIL (HELIX POMATIA) NERVOUS TISSUE IN VITRO
Authors: Osborne N. N.
Published: December 2006

Abstract— When suboesophageal ganglia of the snail Helix comalia were incubated at 25°C in a medium containing [3H]choline, tissue: medium ratios of about 14:1 were obtained after 20 min incubation, and only 15°, of the accumulated choline was metabolized to form [3H]acetylcholine. The uptake of [3H]choline showed saturation kinetics and was dependent upon temperature and sodium ions. Kinetic analysis suggested the existence of a high affinity uptake process (Km= 1.7 μM, Vmax= 0.21 nmol/g/min) and a low affinity process (Km= 100 μM, Vmax= 1.2 nmol/g/min). The high affinity uptake differed from the low affinity system in that it was sensitive to various metabolic inhibitors and was competitively inhibited by low concentrations of hemicholinium‐ and acetylcholine. Neither uptake system was greatly influenced by the absence of calcium, potassium or magnesium ions or by the presence of low concentrations of 5‐HT, dopamine. tetrabenazine, chlorpromazine, decamethonium, nalaxone or imipramine. The high affinity uptake process may be important in supplying choline for the biosynthesis of acetylcholine in cholinergic neurons.