摘要:

AbstractDibutyryl cyclic AMP (DBC) and Nerve Growth Factor (NGF) have both been shown to enhancein vitroneuronal maturation in embryonic sensory ganglia. Since microfilaments and microtubules are known to be involved in neurite elongation, embryonic chick dorsal root ganglia have been treated with cytochalasin B and colcemid in the presence of these growth promoters (DBC or NGF). Established 48‐hr cultures show drastic neurite retraction when treated with either inhibitor. The treatment of cultures with DBC or NGF in the presence of colcemid reverses the inhibitive effects and normal elongation occurs. The growth stimulators, however, are unable to effectively reverse the action of cytochalasin B. These data suggest that increased microtubule assembly is involved in DBC and NGF stimulation of neurite elongation, and hence provide further support for the suggestion that cyclic AMP mediates some of the actions of NG

ISSN:0022-3034    

DOI:10.1002/neu.480040502

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe application of aqueous solutions of tritiated L‐Leucine to the olfactory epithelium of the longnosed garfish (Lepisosteus osseus) results in a rapid sorption of the labeled precursor and the subsequent establishment along the nerve of a profile of labeled macromolecular constituents. This profile consists of a sharp wavefront, a peak and a saddle region. At 23°C, the wavefront enters the nerve 1.8 hr after the isotope application and moves away from the cell bodies at an average rate of 222 ± 2.4 mm/day. As the labeled material is propelled along the nerve fiber, its distribution undergoes several characteristic profile changes. The peak broadens and decreases in height and the slope of the wavefront becomes gradually less steep, while the area of the profile increases. These systematic, time‐dependent changes suggest a redistribution of some of the labeled axonal material during tran

ISSN:0022-3034    

DOI:10.1002/neu.480040503

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

年代:1973

数据来源: WILEY

摘要:

AbstractOrganized cultures of mouse dorsal root ganglia (PNS), cerebellum (CNS), and sympathetic chain ganglia (ANS) were exposed to feeding media containing radioactive Na235SO4for 10 day periods beginning either at the onset of myelination or during myelin maintenance. During this period, the used medium was collected at each of three feedings and frozen. Some cultures were frozen and together with the collected medium were analyzed for mucopolysaccharides (MPS). Sister cultures were fixed in ruthenium red‐glutaraldehyde and processed for [35S] radioautography by light microscopy, and cellular localization of MPS by electron microscopy. [35S] MPS were isolated from both cultures and medium (by alkali treatment, proteolytic digestion, TCA treatment, and dialysis, followed by precipitation with cetylpyridinium chloride and ethanol). Isolated MPS were analysed by paper chromatography after digestion with chondroitinase‐ABC and testicular hyarulonidase. Fifty‐five to seventy‐five percent of the total sulfated MPS formed in all types of cultures were chondroitin sulfates (Ch‐S) A, B, and C,ChS‐A, ChS‐B, and ChS‐C are used throughout to indicate chondroitin ‐4‐ sulfate, dermatan sulfate, and chondroitin ‐6‐ sulfate, respectivelychondroitin sulfate A accounting for 50 to 60% of the total MPS. PNS and ANS exceeded CNS cultures in total sulfated MPS formed by 10:1.Qualitatively, CNS cultures produced a higher proportion of ChS‐C and a lower proportion of ChS‐B compared to PNS and ANS. Rutheniumred positive material covered all types of cell surfaces, collagen fibers, and the surfaces of enveloped axons; the layers of compact myelin and its underlying axon‐Schwann cell interface showed no such staining, though it appeared regu

ISSN:0022-3034    

DOI:10.1002/neu.480040504

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

年代:1973

数据来源: WILEY

摘要:

AbstractA combined morphological and biochemical study was made of the responses of lumbar sympathetic ganglion cells to ligation of their axons in the sciatic nerve of the rat. There was a progressive accumulation of norepinephrine proximal to the ligature for the first few days without detectable changes in the ganglion cells. However, three days after ligation there was a decrease in the axoplasmic accumulation of norepinephrine, accompanied by pronounced falls in ganglion norepinephrine, tyrosine hydroxylase, and monoamine oxidase. These changes, that coincided with the development of signs of chromatolysis in the light and electron microscope, were fully developed one week after ligation and by one month were almost reversed. Proteolysis and death of chromatolytic cells may have made some contribution to the observed changes, but there were no significant changes in the soluble protein content of the lumbar ganglia, presumably because of the counter‐balancing increase in protein synthesis known to occur during chromatolysis and regeneration. It is suggested that axotomy caused a reordering of the priorities of protein synthesis in sympathetic neurones to favor the production of proteins necessary for regenerative rather than transmitter function

ISSN:0022-3034    

DOI:10.1002/neu.480040505

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

年代:1973

数据来源: WILEY

摘要:

AbstractSeven specific enzyme activities were assayed in embryonic mouse spinal cord cultures during normal development and under conditions of myelination inhibition and disinhibition. Sulfatase A activity in the inhibited and disinhibited cultures was slightly lower than in the normal control cultures. No specific differences for glucose‐6‐phosphate dehydrogenase, β‐galactosidase, β‐glucuronidase, acid prosphatase, and NADP‐isocitrate dehydrogenase activities were found among these three experimental conditions. However 2′,3′‐cyclic nucleotide phosphohydrolase, an enzyme which has been specifically associated with myelin, showed identical patterns of inhibition and disinhibition as were previously observed for su

ISSN:0022-3034    

DOI:10.1002/neu.480040506

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

年代:1973

数据来源: WILEY

摘要:

AbstractExplants of substantia nigra and corpus striatum obtained from newborn rats were maintained in tissue culture for up to six days. Explants of substantia nigra exhibited a net increase in the ability to take up H3‐dopamine, a process associated with the dopaminergic neurons; in contrast, the explants of corpus striatum showed a rapid loss in this ability to accumulate H3‐dopamine. After three days in culture, the specific activity of tyrosine hydroxylase and monoamine oxidase had decreased 50% in explants of substantia nigra. A medium including fetal calf serum and chick embryo extracts was necessary for the increase in H3‐dopamine uptake, and nerve growth factor had an inhibitory effect. Histofluorescent examination of nigral explants cultured for three days indicated morphologically normal dopaminergic ne

ISSN:0022-3034    

DOI:10.1002/neu.480040507

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

年代:1973

数据来源: WILEY

摘要:

AbstractSpecific impedance at various depths in the cerebral cortex of the rat was measured using a newly developed thin film coaxial microelectrode. This novel electrode has the advantage of measuring specific impedance of extremely small volumes of tissue, and thus of making highly localized measurements.The resting level of cortical impedance in the rat was found to be stable, but to vary for different sites and animals from 200–700 ohm‐cm. During spreading depression, loop‐shaped impedance loci were consistently observed in the complex impedance plane with peak magnitude 2–3 times resting level. These unusual loop‐shaped loci are thought to represent distinct process differences during development and recovery phases of spreading depression.This preliminary investigation has demonstrated the feasibility of a technique for making highly localized impedance measurements in nervous tissue. Such measurements are useful forin vivostudies of such tissue parameters as extracellu

ISSN:0022-3034    

DOI:10.1002/neu.480040508

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

年代:1973

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480040509

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

年代:1973

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480040501

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

年代:1973

数据来源: WILEY