摘要:

Abstract—The DNA content of mouse Purkinje neurons was investigated employing a biochemical approach. Material for the biochemical assay was provided by means of a sedimentation velocity separation technique which yields bulk quantities of well‐preserved Purkinje perikarya in a high degree of purity. The same amount of DNA/cell was recorded for mixed cerebellar cell somata (7·6 ± 0±2 pg/cell), as for the Purkinje perikarya enriched fractions (7±2&0·2 pg/cell). No evidence could be found for the existence of a tetraploid DNA complement in mouse Purkinje neurons despite indications to the contrary from a parallel cytophotometr

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00025.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—A method is described for the isolation of relatively pure cholinergic synaptic vesicles by hypo‐osmotic shock and density gradient centrifugation of a synaptosome fraction prepared from bovine superior cervical ganglia. Vesicles from this source were found to sediment to a density equivalent to 0·3–0·41 M‐sucrose. The vesicle subfraction from the gradient had an acetylcholine (ACh) content of 4.4 nmol/mg of protein and were subject to leakage of ACh. By a ‘tagging’ technique, the vesicles were counted under the electron microscope and their numbers related to their ACh concentration. After correction for leakage, an ACh content of 1630 molecules/vesicle

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00026.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—(1) The effects of gamma‐hydroxybutyrate, imidazole‐4‐acetic acid and pento‐barbitone on mouse brain glucose, glycogen and lactate levels have been studied. All the drugs significantly increased the brain glucose content, but did not significantly alter brain glycogen levels. The increase in brain glucose following imidazole‐4‐acetic acid or hypnotic doses of pentobarbitone was matched by corresponding decreases in the lactate level; this was not the case with gamma‐hydroxybutyrate where the total glucose equivalents in the brain, expressed as the tissue level of (glucose) + (lactate/2), were significantly increased.(2) All drugs except imidazole‐4‐acetic acid significantly decreased the rate of appearance of [14C]glucose into the bloodstreamin vivobut had no effect on the uptake of glucose into rat diaphragmin vitrowhen present at 2·5 mM concentration.(3) Only imidazole‐4‐acetic acid significantly inhibited glucose uptake into the brainin vivobut at 2·5 mM had no significant effect on glucose uptake into rat cerebral cortical slicesin vitro.(4) It is concluded that the very large increase in brain glucose level observed following the injection of hypnotic doses of gamma‐hydroxybutyrate cannot be explained in terms of an increased net uptak

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—An acidic protein has been isolated from the optic lobes of two cephalopods,Sepia officinalisandLoligo vulgaris.The protein has been obtained in pure form by fractionation with ammonium sulphate and chromatography on DEAE‐cellulose and Sephadex G 100. Its apparent molecular weight is 13,000–15,000. Glutamic and aspartic acids account for 35 per cent of the amino acid residues. The protein binds Ca2+ions with an apparent dissociation constant of 2·5 × 10−5M at physiological concentrations of KCI. Antibodies have been prepared against the protein purified fromSepia officinalis.By the micro‐complement fixation technique it has been shown that the protein is highly concentrated in the nervous system of cephalopods and that the amount in the axoplasm of squid giant axons is eight to nine‐fold higher than in the optic lobes of th

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00028.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—The appearance of the enzymes succinate dehydrogenase, lactate dehydrogenase, acid phosphatase, monoamine oxidase and acetylcholinesterase in cultures of dissociated spinal cord, dorsal root ganglia and cerebellum removed at different stages of development have been studied. The neurons differentiatedin vitrohave morphological and cytochemical characteristics similar to those of the normally developing neurons. On the basis of the results obtained, it is argued that in this experimental model the histogenetic determination of the neuroblasts at the time of the explant may start and bring to an end the morphological and biochemical differentiation of the various types of neurons even under conditions extremely different from those of normal developmen

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00029.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—It was demonstrated after intraperitoneal and intracerebral injections of [1,4‐14C]‐putrescine.2 HCl that GABA is formedin vivoin the trout brain via a pathway in which glutamic acid is not an intermediate. Intraperitoneal and intracerebral injections of both thiosemicarbazide and 3‐mercaptopropionic acid had no measurable effects on GABA concentration, transformation of glutamic acid into GABAin vivo, or on glutamate de‐carboxylase activity in the brain within the first 3 h after the application of the inhibitors. Only a small decrease in concentration of pyridoxal phosphate was noticed in the fish brain after thiosemicarbazide administration. The relatively high concentrations of pyridoxal phosphate in the trout brain may be one of the reasons for the ineffectiveness of thiosemicarbazide in inhibiting glutamate decarboxylasein vivo.After intracerebral injections of [1‐14C]GABA, a half‐life of 7 h was determined for GABA. The slow turnover rate of GABA in trout brain, which can be assumed from this observation, may give a further explanation of the ineffectiveness of the glutamate decarboxylase inhibitors in lowering the GABA content ot fish brain withi

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00030.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—In contrast to mouse brain, the content of putrescine in fish brain considerably exceeds that of spermine and spermidine. While we observed constant protein, RNA and spermidine concentrations in fish brains of weights between 60 and 800 mg, DNA and spermine concentrations diminished with increasing brain weight, the content of spermine per cell being constant throughout life. It can be concluded from our results that growth of fish brain results both from cell enlargement and cell proliferation. The concomitant changes of spermine and DNA concentrations in the growing fish brain are the first example of a direct quantitative relationship between these cell constituents and provides evidence on their possible functional relationship in the cell nucleu

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00031.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—A potentiometric titration method for the assay of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase is presented. Progress curves of the reaction were recorded automatically by pH‐stat. 2‐Mercaptoethanol was added to the reaction mixture to maintain a linear rate of reaction. The method is suitable for obtaining kinetic parameters and can be used for the rapid assay of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase in nervous tissues. An improved colorimetric method for estimation of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase activity at the optimum pH is described. This method employs the two‐step procedure in which decyclization by 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase and dephosphorylation byEscherichia colialkaline phosphatase (EC 3.1.3.1) are carried out separately under the optimum conditions for each enzyme. The method is s

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00032.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Available methods for the determination of homovanillic acid (HVA) are based on fluorimetric measurements. The present method uses gas chromatography‐mass spectrometry with the aid of deuterium labelled HVA methyl ester as a carrier and internal standard. Quantitation is achieved by comparing intensities of the molecular ion (= base peak) of the protium (H) and deuterium (D) forms of the methyl ester heptafluorobutyric derivatives of HVA. A standard curve is constructed by measuring mixtures of known amounts of protium and deuterium derivatives and plotting peak height ratios H/D on the ordinate and ratios of amounts H/D on the abscissa. Analysis of ten individual mouse brains gave a mean value of 1·36 nmole/g brain tissue with a standard deviation of ±9 per cent. Chlorpromazine elevates, whereas pargyline reduces the level of HVA in brain markedly. The described procedure offers advantages because of the greatly increased specificity and sensitivity permitting analyses in discrete brain

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00033.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Putreanine was proven to be formed from spermidine in rat brain by intra‐ventricular injection of radioactive spermidine. The ability to form putreanine from spermidine was also found in rat liver. The turnover rate of putreanine was slower in rat brain than in rat li

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00034.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY