ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Relatively high concentrations of ACh have been found in the head ganglion of the squid (Loligo pealii) and the identity of the ACh has been verified by ion‐exchange chromatography. Following homogenization in media iso‐osmotic with sea water about 40 per cent of the ACh survives in particle‐bound form. Experiments using media of varying osmolarity suggest that this bound ACh is osmotically sensitive. A study has been made of the subcellular fractionation of squid head ganglion using sucrose homogenates. A rapid and novel method is described for the preparation of a synaptosome fraction freed from mitochondria. This preparation contains synaptosomes of well‐preserved morphology with occluded cytoplasm and a high specific content of ACh. The synaptosomes are osmotically sensitive and when suspended in water they burst, releasing cytoplasmic constituents and ACh‐containing synaptic vesicles. The synaptic vesicles can be separated from other sub‐synaptic constituents by density gradient c

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—[3H]Pyridoxine and [3H]pyridoxine 5′‐phosphate have been injected into rats and mice. The uptake in brain tissue has been studied by comparing the concentrations of labelled compounds in serum, cerebrospinal fluid and brain tissue. Labelled pyridoxine passes rapidly into brain tissue, whereas the uptake of pyridoxine 5′‐phosphate occurs at a much slower rate.Perchloric acid extracts of brain have been fractionated by ion‐exchange chromatography and the distribution of isotope between the different forms of the vitamin has been determined at different times after the administration. The time sequence of the metabolic transformation is: pyridoxine+→ pyridoxine 5′‐phosphate → pyridoxal 5′‐phosphate → pyridoxamine 5′‐phosphate. After the initial transformation period about 40 per cent of the isotope is recovered in each of the pyridoxal 5′‐phosphate and py

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—The effect of a number of amino acids on the transparency and on the release of of [14C]glutamate from isolated chicken retinae charged with this compound was investigated. Also the effect of various amino acids on the response of the retina to stimulation with unlabelled glutamate, which causes an increase in transparency and a release of the label, was examined. In parallel experiments the effect of these same amino acids on the transparency and spreading depression (SD) was investigated in preparations consisting of the posterior part of the eye. A number of amino acids such as L‐leucine, L‐phenylalanine, L‐tryptophan, L‐lysine, L‐histidine, L‐arginine and others had little or no effect on these preparations. DL‐valine and DL‐homoserine caused an increase in transparency but no release of the label and did not affect the response to glutamate. Another group of amino acids comprising DL‐a‐alanine, L‐serine, L‐threonine, L‐proline and glycine also caused an increase in the transparency of the retina without a release of labelled glutamate, but prevented the increase in transparency resulting from glutamate stimulation without affecting the release of the label. A final group of amino acids which included L‐glutamic acid diethyl ester, DL‐a‐methyl glutamate, L‐glutamine, L‐asparagine, DL‐homocysteate and L‐cysteine caused a change in transparency of the retina accompanied by a release of the label; they prevented the change in transparency as well as the release of the label during stimulation by glutamate. Some amino acids, L‐serine, L‐threonine, DL‐a‐methyl glutamate, L‐asparagine, DL‐homocysteate and L‐cysteine, caused wrinkling and folding of the retinae which furthermore became opaque. Of the amino acids investigated, proline gave promise of being a practi

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Recoverable myelin in 20‐day‐old, Vitamin B6‐deficient rats was reduced from that in control animals. The composition of myelin lipids from deficient animals was nearly identical to that for controls except for a striking reduction in phospholipids polyunsaturated fatty acids. Enzymatic synthesisin vitroof 3‐ketodihydrosphingosine was impaired in the deficient animals; addition of the vitamin Bs cofactor to these incubation mixtures restored activity of the condensing enzyme to contr

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00066.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Several identified neurons inAplysiaandTritoniaganglia were shown to contain measurable quantities (4–6 pmol/cell body) of 5‐hydroxytryptamine (5‐HT). A metabolic correlate for the limited distribution of 5‐HT among the neurons ofTritoniais provided by the finding that the enzyme, aromatic acid decarboxylase (AAD), is 500 times more active in nerve cells containing 5‐HT than in neurons devoid of the amine. Although allAplysianeurons have some AAD activity, 5‐HT cell bodies in this species are 10‐fold more active than cell bodies which do not contain 5‐HT. The cytoplasm of 5‐HT cell bodies inAplysiaandTritoniacharacteristically contains granules that have minimum diameters of approx. 1000 Å and eccentric opaque cores. This type of granule was not found in somata which did not contain measurable 5‐HT. These data illustrate the metabolic and morphological specialization in 5‐HT‐cont

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00067.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—Rabbits were immunized with chromomembrin B, i.e. a membrane protein isolated from chromaffin granules of bovine adrenal medulla. When the rabbit sera were tested by immunodiffusion in the presence of various detergents, only negative results were obtained, whereas with complement fixation antibodies could be demonstrated. With this method the subcellular distribution of chromomembrin B in bovine adrenal medulla was determined. The results demonstrate that this protein is specifically localized in the membranes of chromaffin granules. In the mitochondrial and microsomal fractions it is present only in small amounts which are attributable to a contamination of these fractions with chromaffin granules. The subcellular distribution of chromomembrin R in bovine splenic nerves indicates that this antigen is also found in the membranes of noradrenalinestoring vesicles of sympathetic nerve. Chromomembrin B or a related antigen was detected in chromaffin grades isolated from pig and rat adrenal and in those isolated from a human phaeochromocytoma. It is also present in total membranes obtained from posterior and anterior hypophysis, but it is absent from membranes isolated from parotid gland, liver and adrenal cortex. This paper illustrates how a membrane protein which requires detergents for its solubilization can be characterized and measured by immunological method

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00068.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—1Intraperitoneal injection of phenobarbitone (250 mg/kg body wt.) into rats caused increased brain concentrations of glucose (100 per cent), glucose 6‐phosphate (16 per cent) and ATP (12 per cent) and decreased concentrations of lactate (33 per cent) and ADP (15 per cent). A 31 per cent decrease in glutamate content was not statistically significant. No significant change occurred in the cerebral contents of glycogen or creatine phosphate.1The rates of increase in the brain of specific activities, in the first few minutes after systemic injection of [U‐14C]glucose, of glucose, lactate, glutamate and glycogen were all halved by phenobarbitone. Calculated flux rates of14C from glucose into metabolic intermediates and from lactate to glutamate were also decreased by 27–47 per cent; the effects on rate constants showed inconsistencies. The rate constants for conversion of glucose to lactate and to glutamate were decreased by 60–70 per cent, but that from lactate to glutamate was virtually unchanged. The rate constant for the flux from glucose to glycogen was reduced by 39 per cent, but the accumulation of glucose meant that the actual flux into glycogen increased by 20 per cent.1The results are interpreted in terms of an effect of the barbiturate not only on glucose transport, but also at an enzymic stage in glycolysis, possibly hexokinase or phosphofru

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00069.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—The composition and content of gangliosides from rat‐brain microsomal, synaptosomal, mitochondrial and myelin fractions were studied. Outer membranes of synaptosomes were also isolated, separated into subfractions and investigated. Of all the fractions studied the outer membranes of synaptosomes are richest in gangliosides, in one of their sub‐fractions the concentration of gangliosides per mg of protein is five times higher than in the homogenate. Microsomes are rich in gangliosides as well, but to a lesser degree, whereas the mitochondrial fraction contains considerably smaller amounts of gangliosides per mg of protein than does the homogenate. The ganglioside pattern of outer membranes of synaptosomes and of their subfractions is somewhat different from that of the homogenate; the outer membranes contain approximately one‐third less monosialogangliosides. On the contrary a very high content of monosialogangliosides is characteristic of the ganglioside pattern of the myelin fraction. In this fraction monosialoganglioside GMI(nomenclature of Svennerholm, 1963) constitutes 60–63 per cent of ganglioside sialic acid, or 75–80 molar per cent of gangliosides, the content of di‐ and trisialogangliosides being much lower than in other fractions. Fatty acid and long chain base composition of gangliosides from synaptosomal and microsomal fractions and homogenate is very similar, almost identical. In gangliosides from myelin fractions the relaitve content of palmitic and monoenoic acids is higher and that of arachinic acid and C20‐sphingosine—lower than in other fractions studied. The difference in ganglioside composition of synaptosomes and their outer membranes and on the other hand of myelin appears to reflect the difference in ganglioside composition of neuronal and oligodendroglial

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00070.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract—The regional and subcellular distribution of the glycine decarboxylation which occurs in the presence of tetrahydrofolate, NAD and pyridoxal phosphate, has been measured in CNS tissue of cat, sheep and rat. The activity appeared similar to that of liver. It was located within mitochondria, and distributed regionally and subcellularly in the same manner as succinate dehydrogenase, a mitochondrial marker. Activity was low in pons, medulla and spinal cord, and was not affected by a number of drugs, some of which excite and some of which depress the activity of the CNS. All evidence suggests that glycine decarboxylation plays no direct role in glycine inhibitory transmissio

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1973.tb00071.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY