ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04502.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04503.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractAmphetamine, a potent sympathomimetic amine, has powerful stimulant actions in the central nervous system. These actions are believed to be related to the influence of amphetamine on release and uptake of catecholamine neurotransmitters. The [14C]deoxyglucose method makes it possible to study changes in cerebral metabolic rate in different areas of gray and white matter. Because of the close relationship between metabolic rate and functional activity, this method may be used to identify specific structures in the brain in which functional activity is altered. The [14C]deoxyglucose method was used to explore for changes in metabolic rate produced byd‐andl‐amphetamine (5 mg/kg) in forty gray and four white matter structures in normal conscious rats.d‐Amphetamine produced increases in local cerebral glucose utilization in a number of components of the extrapyramidal motor system, as well as in some other structures known to contain dopamine‐producing and/or dopaminoceptive cells. The largest increases afterd‐amphetamine administration occurred in the subthalamic nucleus and the zona reticulata of the substantia nigra.l‐Amphetamine produced increases in some but not all of these same structures, and these were generally smaller than those observed with d‐amphetamine. Decreases in local cerebral glucose utilization after eitherd‐ orl‐amphetamine administration were found in the habenula and the suprachiasmatic nuclei of the hypothalamus. The effects in the suprachiasmatic nuclei may reflect their normal diurnal rhythm in metabolic rate. These results indicate that amphetamines may influence behavior through effects on specific regions of the brain. Only some of these regions have previously been studied as possible sites of acti

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04504.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe effect of a single systemic injection of reserpine on tyrosine hydroxylase activity in the locus coeruleus, cerebellum, hypothalamus, and hippocampus was examined. Increases in enzyme activity were seen in all four brain areas; the time‐course of the changes, however, was different in each case. In the locus coeruleus the maximum change in enzyme activity was seen 3 days after drug administration; in the cerebellum, 7‐11 days; in the hypothalamus, 8‐11 days; and in the hippocampus, 21 days. Since tyrosine hydroxylase in the cerebellum and hippocampus is present in terminals of neurons whose cell bodies are located in the locus coeruleus, the delayed increase in enzyme activity in cerebellum and hippocampus probably depends upon the slow rate of transport of TH molecules in these ne

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04505.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstractpineal acetyl‐CoA hydrolase is measurable at 4 days before birth. It increases rapidly to a maximum of 0.37 nmol/min/0.1 mg protein during the first week after birth, thereafter gradually decreasing and stabilizing at adult levels (0.27 nmol/min/0.1 mg protein) 3‐4 weeks after birth. Unlike A/‐acetyltransferase, the activity of acetyl‐CoA hydrolase does not increase following treatment with isoproterenol, does not exhibit a circadian rhythm and is not inactivated on exposure of the animals to light at night. In addition, denervation of the pineal gland does not alter acetyl‐CoA hydrolase

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04506.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe glycoproteins of the membranes of bovine chromaffin granules were characterized by two polyacrylamide gel electrophoresis systems. Five components (I‐V) were demonstrated with apparent molecular weights ranging in the unreduced form from 45,000 to 150,000. Glycoprotein I was identified as the enzyme dopamineβ‐hydroxylase. Four of these glycoproteins (with the exception of component IV) were apparently also present in the membranes of pig and horse chromaffin granules. The soluble proteins of chromaffin granules contained at least three glycoproteins. Only glycoprotein I (dopamineβ‐hydroxylase) was present both in the soluble content and in the membranes of chromaffin granules. Affinity chromatography with lectins demonstrated that from the soluble proteins only dopamineβ‐hydroxylase was adsorbed by concanavalin A, whereas none of these proteins reacted with wheat germ lectin and Ricinus communis agglutinin. Three membrane proteins including dopamineβ‐hydroxylase and glycoprotein II as major components were adsorbed by concanavalin A, whereas wheat germ lectin bound only component II and a small amount of component III. By electron microscopy it was demonstrated that concanavalin A did not bind to intact chromaffin granules whereas ruthenium red and cationized ferritin did. Isotope labelling after galactose oxidase treatment revealed that at least the carbohydrate portion of the major glycoproteins is present on the inner side of the granule membranes facin

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04507.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe effects of chronic administration of clorgyline and pargyline on rat brain monoamine metabolism have been examined. The inhibitory selectivity of these drugs towards serotonin deamina‐tion (MAO type A) and phenylethylamine deamination (MAO type B) can be maintained over a 21‐day period by proper selection of low doses of these drugs (0.5‐1.0 mg/kg/24h). The results are consistent with MAO type A catalyzing the deamination of serotonin and norepinephrine and with MAO type B having little effect on these monoamines. Dopamine appears to be dcaminatedin vivoprincipally by MAO type A. Clorgyline administration during a 3‐week period was accompanied by persistent elevations in brain norepinephrine concentrations; serotonin levels were also increased during the first 2 weeks, but returned towards control levels by the third week of treatment. Low doses of pargyline did not increase brain monoamine concentrations, but treatment with higher doses for 3 weeks led to elevations in brain norepinephrine and 5‐hydroxytryptamine; at this time significant MAO‐A inhibition had developed. The changes in monoamine metabolism seen at the end of the chronic clorgyline regimen are not due to alterations in tryptophan hydroxylase activity. At this time tyrosine hydroxylase activity was also

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04508.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe cerebellar nerve cell line ε1has a very effective active transport system for glutamate. Glutamate uptake is dependent on extracellular Na+and furthermore,22Na+uptake is stimulated by glutamate, indicating that glutamate uptake and Na+uptake are coupled. Two molecules of Na+are transported for each molecule of glutamate. TheKmfor glutamate is found to be 5 × 10−5M in both the glutamate uptake assay and the22Na+uptake assay, providing additional evidence for glutamate‐Na+coupling. Pre‐incubation with ouabain, which inhibits the Na+‐K+ATPase, results in a gradual inhibition of glutamate uptake due to the deterioration of the Na+gradient. Tetrodotoxin, however, has no effect on glutamate‐induced22Na+uptake, showing that this Na+flux does not occur via voltage‐dependent Na+channels. Studies on the specificity of the ε1glutamate transport system show that it is distinct from systems that transport alanine and glycine.l‐Glutamate,d‐aspartate,l‐cysteate, andl‐cysteine sulfinate are able to utilize the transport system efficiently.d‐Glutamate,l‐homocysteate,N‐methyl‐d,l‐aspartate, and kainic acid are very poor substrates for the glutamate transport system, and in addition do not stimulate22Na+uptake. These data allow us to distinguish the glutamate transport system from the glutamate receptor which is known to mediate depolarization in response to all nine of the above compounds. Thus, ε1does not have

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04509.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractBrain cortex slices from fed, 48 h and 120 h fasted rats were incubated and14CO2was measured from (a) [U‐14C]glucose (5 mm) either alone or in the presence ofl‐lcucine (0.1 or 1 mm), and (b) [U‐14C]leucine or [l‐14C]leucine at 0.1 or 1 mmwith or without glucose (5 mm). In other experiments, sodiumdl‐3‐hydroxybutyrate (3‐OHB) or acetoacetate (AcAc) at 1 or 5 mmwere added in the above incubation mixture. The rate of conversion of [U14C]glucose to CO2was decreased 20% by leucine at 1 mmand 30–50% by 3‐OHB at 1 or 5 mmbut not by leucine at 0.1 mm. The effects of 3‐OHB and of leucine (1 mm) were not additive. The effects of leucine were similar in the fed and fasted rats. The rate of conversion of [U‐14C]leucine or [l‐,4C]leucine to14CO2at 0.1 mmand 1.0 mmwas increased by glucose (35%) in the fed or fasted rats. Ketone bodies in the absence of glucose had no effect on leucine oxidation. However, the stimulatory effect of glucose on the rate of conversion of leucine to CO2was inhibited by 3‐OHB at 5 mm. These results suggest that (a) leucine in increased concentrations (1 mm) may reduce glucose oxidation by brain cortex while itself becoming an oxidative fuel for brain, and (b) leucine oxidation by brain may be influenced by the prevailing glucose

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04510.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe presence of a sequestered encephalitogenic determinant for Lewis rats in the bovine myelin BP was demonstrated with synthetic peptide sequences prepared in our laboratory by the Merrifield solidphase method. The sequence of the encephalitogenic determinant (residues 75‐84) from bovine BP (peptide S6), H‐Ala‐Gln‐Gly‐His‐Arg‐Pro‐Gln‐Asp‐Glu‐Asn‐OH, is similar but not identical to the sequence reported for the guinea pig BP (peptide S53), H‐Ser‐Gln‐(–)‐(–)‐Arg‐Ser‐Gln‐Asp‐Glu‐Asn‐OH. The presence or the absence of Gly‐His from the sequence of either the bovine or the guinea‐pig determinants did not alter their encephalitogenic potencies; however, the presence of Gly‐His at positions 77 and 78 together with H‐Gly‐Ser‐Leu‐Pro‐Gln‐Lys‐ (residues 69‐74) at the N‐terminal end of the bovine determinant destroyed its encephalitogenic potency.In contrast to the absence of Gly‐His from the potent encephalitogenic guinea‐pig BP, guinea‐pig fragment 44‐89, and synthetic peptide S49, its presence in the bovine sequence prevents recognition of this determinant and renders the parent bovine BP, bovine fragment 44‐89, and synthetic peptide S8 (residues 69‐84) relatively non‐encephalitogenic. The results of this study suggest that intramolecular interactions occur between adjacent amino acids, conferring secondary or tertiary structures upon this region of the bovine BP which renders the encephalitogenic determinant inaccessible for recognition by the host animal. The presence of sequestered disease‐ind

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1979.tb04511.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY