Restorative Neurology and Neuroscience - Volume 3, issue 6

Authors: Marsala, Martin | Vanicky, Ivo | Radonak, Jozef | Kliesenbauerova, Eva | Marsala, Jozef

Article Type: Research Article

Abstract: This study evaluated whether or not reperfusion of the rabbit ischemic spinal cord under conditions of varying blood oxygen tension combined with low blood viscosity can alter the neurological outcome after 15 min of infrarenal aortic occlusion. In group A (n = 20), hyperoxic reperfusion was performed during the initial 30 min of recirculation (pO2 = 460 ± 72 mmHg). In group B (n = 20), no attempt was made to manipulate the physiological arterial pO2 tension. In group C (n = 20), graded postischemic reoxygenation was applied during 15 min of recirculation beginning with 48 ± 12 …mmHg as the initial arterial pO2 . Neurological analysis revealed a high incidence of paraplegic animals after hyperoxic reperfusion as opposed to relatively undamaged animals after normoxic or graded postischemic reoxygenation. The possible role of different pathobiochemical events, specifically the high molecular oxygen availability and oxygen free-radical overproduction, is discussed below with attention to the interneuronal destructive process, detected during the early reoxygenation phase by means of the Nauta method permitting the visualization of the early signs of somatic and dendritic argyrophilia. Show more

Keywords: Ischemia, Spinal cord, Postischemic hyperoxia, Neurological recovery

DOI: 10.3233/RNN-1992-3601

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 283-291, 1992

Authors: Sharkey, J. | Kelly, P.A.T.

Article Type: Research Article

Abstract: The pharmacological characteristics of both muscarinic receptors and high-affinity choline uptake sites were examined within intracerebral implants of foetal basal forebrain cell suspensions. Approximately 12 weeks after implantation, the transplants were identified by acetylcholinesterase histochemistry. Muscarinic receptors were labelled by [3 H]quinuclidinyl benzylate (QNB) autoradiography. The M1 and M2 receptor components of QNB binding were differentiated by pirenzepine competition. The distribution of the high-affinity choline uptake site was examined using [3 H]hemicholinium-3 (HC3) autoradiography. Unilateral lesion of the nucleus basalis reduced [3 H]QNB (8–25%) and [3 H]HC3 (19–43%) binding throughout host frontoparietal cortex ipsilateral to the lesion but …did not significantly alter these cholinergic markers within cingulate cortex, subcortical white matter, striatum or septum. Saturation analysis of the implanted tissue revealed the presence of a single population of [3 H]QNB and [3 H]HC3 binding sites with affinities similar to those of the host tissue (KD = 0.43 nM and 20.4 nM respectively). However, the receptor profile which developed appeared to be intrinsic to the implant; it was unaffected by the site of implantation and was dissimilar to that which ultimately developed in the donor tissue when left in situ. Show more

Keywords: Intracerebral transplant, Quantitative autoradiography, Muscarinic receptor, Choline-reuptake sites

DOI: 10.3233/RNN-1992-3602

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 293-300, 1992

Authors: Sonnentag, U. | Rösner, H. | Rahmann, H.

Article Type: Research Article

Abstract: In the present study, the left optic nerve of the goldfish was transected between eye bulb and optic chiasm. One to 39 days after lesion, the fish received an intraperitoneal injection of [3 H]proline or [3 H]NAc-glucosaraine. After one or two days of incorporation, both retinae and optic nerves were analyzed for protein- and ganglioside-bound radioactivity. A transient enhancement of label incorporation into proteins (up to 2-fold) and gangliosides (up to 1.5-fold) of the regenerating retina was found. Simultaneously, a transiently enhanced accumulation (up to 4.5-fold) of protein- and ganglioside-bound radioactivity in the regenerating optic nerve took place. These regeneration-related …‘metabolic’ changes came to a maximum at 6–8 days after nerve transection and were still measurable after 40 days. In the regenerating retina, there were no changes either of the ganglioside pattern or of the relative distribution of radioactivity of individual gangliosides. In the regenerating optic nerve, however, ganglioside GPlc, identified by immuno-TLC, and a fraction migrating like GD3/GM1 were enhanced with respect to their relative proportion of total ganglioside sialic acid and radioactivity. The radioactivity proportion of a ganglioside migrating like GDlb was decreased. Show more

Keywords: Goldfish optic system, Regeneration, Gangliosides, Proteins, Metabolism, Thin-layer chromatography

DOI: 10.3233/RNN-1992-3603

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 301-310, 1992

Authors: Jørgensen, Ole S. | Stein, Donald G.

Article Type: Research Article

Abstract: Transplants of fetal brain tissue or injections of ganglioside GM1 , given to rats with unilateral, left medial frontal cortex lesions, altered the concentrations of neuronal and glial marker proteins in cortex both adjacent and contralateral to the lesion. The markers were: the neural cell adhesion molecule (NCAM) and D3-protein, both present in neuronal and synaptic membranes; synaptophysin, present in synaptic vesicles; glial fibrillary acidic protein (GFAP) enriched in reactive astrocytes, and the astrocytic glutamine synthetase. After 21 days the concentrations of NCAM, D3 and synaptophysin in brain tissue adjacent to the lesions were decreased by 39, 32 and 42%, …respectively, indicating neuronal damage. In the injured rats the GFAP concentration was increased 77%, indicating activation of astrocytes. However, astroglial proliferation was not altered as indicated by the nearly unchanged glutamine synthetase concentrations. The levels of the neuronal markers NCAM, D3 and synaptophysin showed significantly less decline in injured rats treated 7 days after the lesions with transplants or with daily injections of 30 mg/kg GM1 . The decrease respectively constituted 23 (NCAM), 31 (D3) and 41% (synaptophysin) in rats with transplants and 23 (NCAM), 16 (D3) and 28% (synaptophysin) in rats treated with GM1 . In another group of rats the efficacy of transplants was studied 34 days after lesions. NCAM and D3 in tissue adjacent to the lesions were decreased by 50 and 29%, respectively. In rats which received transplants the decrease was only 27 and 16%, respectively. Moreover, as measured by GFAP concentration, activation of astrocytes was less in rats with transplants (93% increased) compared with rats with lesions only (163%). In contralateral frontal cortex, the effects of lesions were similar but less pronounced. In this brain area also the treatments significantly counteracted the loss of neuronal and glial markers. Previous studies have demonstrated that synaptic remodelling is reflected by the ratios of NCAM to marker proteins for mature synapses. Twenty-one days after the initial injury to the brain the ratios of NCAM to D3 and synaptophysin were significantly increased in frontal cortex ipsilateral to the injury in rats with transplants (26 and 33%, respectively). In contrast, compared with values for injured rats, the calculated ratios were not changed, whereas all neuronal marker proteins were significantly increased in rats treated with GM1 . The results suggest that transplants mediate neuronal recovery by inducing dendritic sprouting followed by synaptic remodelling whereas gangliosides mediate recovery by counteracting neuronal degeneration. Show more

Keywords: Rat frontal cortex, Brain injury, Lesions, Transplants, Neuronal proteins, Neural cell adhesion molecule, NCAM, D3, synaptophysin, Glial fibrillary acidic protein, Glutamine synthetase, Gangliosides, GM1

DOI: 10.3233/RNN-1992-3604

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 311-320, 1992

Authors: Goldschmidt, Richard B. | Steward, Oswald

Article Type: Research Article

Abstract: Granule cells of the dentate gyrus can be selectively destroyed by intrahippocampal injections of colchicine. The present study evaluates the consequences of this selective neuronal destruction on the afferent axon terminals which have been deprived of their normal targets. The area of the neuropil in the dentate gyrus (the molecular layer) was evaluated in sections stained using the Timm's method for heavy metals, which selectively marks the terminal fields of the different afferent systems. The molecular layer was examined electron microscopically to determine the fate of afferent terminals. Anterograde transport of HRP or [3 H]proline was used to define the …location and extent of afferent terminal fields of the entorhinal and commissural projections to the dentate gyrus in which the granule cells had been destroyed. There was a substantial reduction in the size of the dentate gyrus molecular layer after destruction of granule cells with colchicine. Electron microscopic analyses revealed that there were very few axon terminals or synapses remaining in the shrunken molecular layer. Tract tracing methods revealed that both the entorhinal and commissural pathways were still present in their normal terminal zones in the dentate gyrus, however, the density of the projections was greatly reduced. There was no evidence to suggest the formation of ectopic projections to unusual locations, such as the contralateral dentate gyrus. Pathways passing through the hippocampus appeared to survive the colchicine injections. These results suggest that target destruction in adult animals leads to the disappearance of the afferent axon terminals which normally innervate the cells which die. Show more

Keywords: Dentate gyrus granule cell, Axonal arborization, Colchicine, Soma size, Entorhinal cortex, Hippocampus, Neurotoxin

DOI: 10.3233/RNN-1992-3605

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 321-334, 1992

Authors: Goldschmidt, Richard B. | Steward, Oswald

Article Type: Research Article

Abstract: Studies in developing animals have documented that manipulations which increase or decrease the size of a neuron's axon arbor lead to increases or decreases respectively in the size of the neuron's soma. The present study evaluates whether similar dependencies exist in adult animals, by analyzing changes in cell size in the entorhinal cortex after selective destruction of dentate granule cells with colchicine. Neurons in layer II of the entorhinal cortex which had been deprived of their normal targets decreased in size by 32% relative to their contralateral homologs. Neurons in layer III which project to regio superior of the hippocampus …were affected to only a slight extent, decreasing in size by 8% relative to their contralateral homologs. Neurons in layer V, which do not project to the hippocampus, were unaffected by colchicine injections into the hippocampus. These results indicate that neurons in adult animals which retract terminal arbors as a consequence of target loss also decrease in size. Show more

Keywords: Dentate gyrus granule cell, Axonal arborization, Colchicine, Soma size, Entorhinal cortex, Hippocampus, Neurotoxin

DOI: 10.3233/RNN-1992-3606

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 335-343, 1992

Authors: Gilchrist, Darrin P.D. | Darlington, Cynthia L. | Smith, Paul F.

Article Type: Short Communication

Abstract: Following unilateral labyrinthectomy (UL), spontaneous nystagmus (SN) was measured in guinea pigs which received i.m. injections of 100 or 400 µg/kg ACTH(4-10) or 800 µg/kg [D-Phe7 ]ACTH(4–10), every 4 h for 48 h post-UL. The results were compared to those from a previous study, conducted under identical conditions, in which guinea pigs received similar injections of 200 µg/kg ACTH(4–10) or 0.1 ml/kg saline. ACTH(4–10) significantly accelerated the rate of compensation of SN at 100, 200, and 400 µg/kg doses, although the average effects were larger for the 200 µg/kg condition. [D-Phe7 ]ACTH(4–10) significantly increased the frequency of SN following UL …compared to saline-treated animals; however, it also accelerated the rate of SN compensation. These results indicate that the acceleration of SN compensation in guinea pig by ACTH(4–10) follows an inverted U-shaped dose-response curve and that [D-Phe7 ]ACTH(4–10) increases the frequency of SN. Show more

Keywords: Vestibular compensation, ACTH(4–10), Neuropeptide hormones, Lesion-induced plasticity

DOI: 10.3233/RNN-1992-3607

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 345-348, 1992

Article Type: Other

DOI: 10.3233/RNN-1992-3608

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 6, pp. 349-351, 1992