摘要:

AbstractThe myelin proteolipid has been studied by the electroblot method of Towbin et al [1979]. Samples were separated by SDS–polyacrylamide gel electrophoresis, transferred to nitrocellulose, and incubated with proteolipid antibody. The proteolipid band could be identified immunologically in CNS myelin and in whole brain homogenates. No proteolipid was detected in PNS myelin. Proteolipid from human, bovine, rat, and mouse myelin all cross‐react when analyzed by this method. No cross‐reactivity was indicated between proteolipid and myelin basic pr

ISSN:0360-4012    

DOI:10.1002/jnr.490070102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe relationships has been sttudied between a high and a low molecular weight form of a bovine cardiac factor that supports the survival of avian ciliary ganglionic neurones in culture. Reversible dissociation of the high molecular weight from into identical or similarly sized subunits of apparent molecular weight in the range 15,000–30,000 has been demonstrated. In addition, other inactive high molecular weight components of cardiac extract were found to interact synergistically with both active forms of the facto

ISSN:0360-4012    

DOI:10.1002/jnr.490070103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractUptake kinetics for glutamate, GABA, and glutamine were determined in primary cultures of cerebral neurons, a predominatly GABA‐ergic cell population, and of cerebellar granule cells, a predominantly glutamatergic cell population. A specially high Vmaxfor GABA uptake into the former and for glutamate uptake into the latter cells suggests that considerable amounts of released transmitters may be reaccumulated into appropriate nerve terminals. Nervertheless, the glutamate uptake into the cerebellar granule cells was less intense than that previously observed into corresponding cultures of astrocytes, whereas GABA was accumulated more intensely into neurons than into astrocytes. This suggests that especially glutamatergic neurons may be depleted for their transmitter by accumulation into adjacent astrocytes. If a glutamine flow from astrocytes back to neurons served the purpose of balancing this transfer, it should be expected that glutamine accumulation was more intense in the glutamatergic than in the GABA‐ergic cell population. This was not the case, suggesting that such a glutamate–glutamine cycle may not be operating to a major e

ISSN:0360-4012    

DOI:10.1002/jnr.490070104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractMuscimol, a GABA agonist, enhanced pentobarbital sleeping time in a dose‐dependent manner. The GABA antagonists such as bicuculline and picrotoxin, and the CNS stimulant such as pentylenetetrazol, inhibited pentobarbital sleeping time; however, all except picrotoxin produced less than 35% maximum inhibition. Picrotoxin, an agent which blocks the chloride ionophore of GABA‐receptor complex, exhibited a parallel dose‐response curve with respect to muscimol. Chronic administration of pentobarbital by pellet implantation induced tolerance as evidenced by decreased sleeping time; the tolerance receded gradually upon abrupt withdrawal. Muscimol enhanced pentobarbital sleeping time both in tolerant and withdrawal mice. Na+‐independent GABA‐receptor binding, using [3H]muscimol as a ligand, was increased after acute and chronic pentobarbital administration; withdrawal of the pentobarbital reversed the increase in receptor population. None of the treatments altered the affinity of [3H]muscimol binding. These results support the contention that pentobarbital (a) directly acts on the postsynaptic chloride ionophore and (b) augments GABA‐mediated postsynaptic effects. The functional significance of the increase in GABA receptor population after pentobarbital treatment

ISSN:0360-4012    

DOI:10.1002/jnr.490070105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe receptive fields of the sensorimotor cortex neurons identified by electrocutaneous stimulation were modified by microelectrophoretically applied picrotoxin which is known to reduce inhibition. A relatively short application of picrotoxin (90 nA during 3–6 min) markedly increased the size of the neuronal receptive fields in the sensorimotor cortex. Control application of glutamate showed that additional depolarization did not affect receptive fields of the spontaneously active units. Our results together with other work in this field further support the hypothesis that inhibitory processes play a major role in forming functional properties of the cerebral cortex neuron

ISSN:0360-4012    

DOI:10.1002/jnr.490070106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractBased upon data obtained with our arterio‐venous technique for the determination of cerebral metabolism in humans in vivo we have proposed a method for the determination of cerebral regional intermediary glucose metabolism in humans in vivo using specifically labeled11C‐glucose and positron emission transverse tomography (PETT). In it we would give the subject successive intravenous injections of [3,4‐11C] glucose, [2,5‐11C] glucose and [1‐11C] glucose. There would be a 30 min period of continuous PETT measurements following each injection and a 2 hr interval after the first and second injections. The data would be used with suitable equations and algorithms to estimate for each specific region of the subject's brain the dynamics of the Embden‐Meyerhof‐Parnas (EMP) and the tricarboxylic acid cycle (TCA) metabolic pathways and the incorporation of glucose carbons into lactate, and the extent of dilution of glucose carbons in traversing the TCA with their subsequent incorporation into other carbon pools of the brain (ie, glutamate, glutamine, GABA, alanine). Using14C as a model for11C and autoradiographs made with rat brain slices, we have produced an animal model to demonstrate the feasibility of our proposed method. The resulting autoradiographs have provided evidence of the validity of the predictions made from our arterio‐venous data. The model was employed to show the selective reductions in the rates of incorporation of specific carbon atoms of glucose into regions of the rat brain and evidence of altered metabolic pathways following a single electroconvulsive shock (ECS) and after a ser

ISSN:0360-4012    

DOI:10.1002/jnr.490070107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractExperiments were conducted with the aid of intracellular microelectrodes to study physiological properties of neuropile glial cells in the central nervous system of the medicinal leech. The results showed significant contributions of both K+and Cl−ions to the membrane potential. The transmitter substance 5‐hydroxytryptamine increased the K+conductance of the cell membrane. On the basis of these experiments, a model for potassium homeostasis in leech neuropile is suggested, according to which excess K+ions in the extracellular space lead to passive KCl fluxes across the glial cell membrane and the transmitter 5‐hydroxytryptamine induces a K+release from glial cells into the extracellular space. Since 5‐hydroxytryptamine is known to be an inhibitory transmitter in the leech central nervous system, this release will occur in regions with inactive neurons, which may be specially well suited for neuronal reaccumulation of

ISSN:0360-4012    

DOI:10.1002/jnr.490070108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractExperimental hypoxia led to changes in carbohydrate‐containing macromolecules located on the microsomal and synaptosomal membrane surface. It was found that hypoxia reduced the external membrane‐bound sialic acid content in microsomal and synaptosomal fractions.On the other hand, a decrease in fucose content of proteins in hypoxic synaptosomal fraction was found. Similarly, a decrease was observed in the amount of3H‐labeled concanavalin A bound to the microsomal and synaptosomal glycoprotein fractions. Treatment of microsomal and synaptosomal fractions with galactose oxidase followed by reduction with tritiated potassium borohydride resulted in a significantly higher incorporation rate of tritium into the hypoxic membranes. This was accompanied by an increase in the endogenous glycoprotein galactose transferase activity both in microsomal and synaptosomal frac

ISSN:0360-4012    

DOI:10.1002/jnr.490070109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490070110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490070111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY