Restorative Neurology and Neuroscience - Volume 10, issue 1

Authors: Bach-y-Rita, Paul

Article Type: Other

Keywords: Neurotransmission, Brain plasticity, Non-synaptic diffusion neurotransmission, Functional localization, Neurologic rehabilitation

DOI: 10.3233/RNN-1996-10101

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 1-3, 1996

Authors: Bertelli, Jayme Augusto | Taleb, Madjid | Mira, Jean Claude | Calixto, Joao Batista

Article Type: Research Article

Abstract: In 1921, Ney introduced the concept of nerve grafts with preservation of the vascular blood supply. Today, over 70 years later, the use of vascularized nerve grafts in clinical practice is still controversial. Although the results of experiments with vascularized and conventional nerve grafts have been compared on the basis of electrophysiological and histological observations, the literature includes no vaJid comparison of the clinical and behavioral significance of these results. Therefore, in the experiments reported here, the rat median nerve was repaired using either a vascularized or a conventional ulnar nerve graft. The rates behavior between 0 and 360 days …after surgery was assessed by the grasping test. Nienty-five, 120, 150, 210 and 360 days after surgery rats were submitted to retrograde labeling studies and muscle samples were removed and studied using routine hematoxilin-eosin and ATPase histochemistry. The present study provides evidence that autografting is a reliable procedure for nerve repair. Motor axons were able to reinnervate and largely respecify muscle properties. Reinnervation was not selective either at the nerve trunk level or at the muscle fiber. A mechanism of collateral pruning might have been present in the early phases of reinnervation. This mechanism was, however, self limiting and unable to correct all wrong projections. A mechanism of terminal sprouting was in part responsible for time-related improvement in muscle force recovery. While the present study does provide evidence that recovery was 20% faster in rats with vascularized grafts than in those with conventional grafts (P < 0.0001), it does not, however, provide evidence for better functional recovery in long-term assessment. Show more

Keywords: Peripheral nerve, Nerve repair, Nerve regeneration, Brachial plexus, Nerve grafts

DOI: 10.3233/RNN-1996-10102

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 5-12, 1996

Authors: Aznar, Susana | Tønder, Niels | Azcoitia, Iñigo | Sørensen, Jens Christian | Zimmer, Jens

Article Type: Research Article

Abstract: Exchange of nerve connections between developing neural grafts and adult recipient brains is enhanced for grafts placed in excitotoxic lesions, which spare recipient brain afferent axons in otherwise neuron-depleted lesion areas. In previous studies of hippocampal grafts placed in such lesions, we have used anterograde axonal degeneration, histochemical Timm staining and acetylcholinesterase to demonstrate host-graft interconnectivity. In this study, we have now used three anterograde axonal tracers, Phaseoulus vulgaris-leukoaglutinin (PHA-L), biocytin and biotinylated dextran amine (BDA), which allow individual fibers to be traced. Adult male rats with 1-week-old axon-sparing ibotenic acid lesions of the dorsal CA3 region or fascia dentata …were grafted into the respective lesions with suspensions of fetal (El8–19) CA3 cells or a block of neonatal fascia dentata tissue. One to twelve months later, recipients were injected with Phaseoulus vulgaris-leukoaglutinin or biocytin in the hippocampus contralateral to the graft to trace the possible ingrowth and distribution within the transplants of host commissural axons, or into the transplants with biotinylated dextran amine in order to trace outgrowing graft fibers. In rats with succesfull host Phaseoulus vulgaris-leukoaglutinin or biocytin injections, the CA3 and fascia dentata transplants were innervated by labelled host commissural fibers. In the dentate transplants, most commissural fibers projected as normally to the inner part of the molecular layer, with fewer aberrant fibers extending more superficially into the molecular layer. Following injections into the fascia dentata and CA3 grafts of biotinylated dextran amine, labelled graft fibers were traced into the ipsilateral host dentate hilus, CA3 and CA1. From some CA3 containing grafts, a few labelled fibers were also observed passing through the host fimbria-fornix to the lateral septum on the grafted side. A few fibers were projected as far as to the most septal levels of the contralateral CA1. Show more

Keywords: Neural transplants, Axon growth, Ibotenic acid, CA3 pyramidal cells, Dentate gyrus, Phaseolus vulgaris leukoaglutinin, Biocytin, Biotinylated dextranamine

DOI: 10.3233/RNN-1996-10103

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 13-24, 1996

Authors: Gudiño-Cabrera, Graciela | Nieto-Sampedro, Manuel

Article Type: Research Article

Abstract: Regenerating nerve fiber sprouts enveloped by olfactory bulb (OB) ensheathing cells (ECs) seem to escape the inhibitory influence of gliotic tissue. Accordingly, these cells may be useful for general repair of injured CNS. Relatively large numbers of ECs could be purified from confluent cultures of adult rat olfactory bulb using immunomagnetic beads. Viable ECs could be cultured and purified in good yield from OB dissected up to 18 h post-mortem. Purified ECs could be stored frozen at −75°C for at least 6 months, while maintaining 95% viability. ECs labelled with the fluorescent cell-linker PKH-26 neither shed the label nor exchanged …it with other cells. The migration of labelled ECs transplanted to adult hippocampus was examined at intervals ranging from 3 h to 30 days. Active migration from the injection site was first observed 4 days after transplantation, when ECs appeared intercalated between the neurons of the hippocampal and dentate cell layers. Some ECs remained in that location after 30 days but, at that time, the olfactory glial cells could be observed in loci as distant and diverse as the laterodorsal thalamic nuclei, internal capsule, arcuate nucleus, cerebral aqueduct walls and choroid plexus. ECs seemed to have preferences for the dentate hilus, the pyramidal and granular cell layers, choroid plexus, blood vessels and putative peptidergic loci. Show more

Keywords: Regeneration, p75 NGF receptor, Immuno-purification, Cryopreservation

DOI: 10.3233/RNN-1996-10104

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 25-34, 1996

Authors: Naidu, Murali D.K. | Subramaniam, Krishnan | Vrbová, Gerta

Article Type: Research Article

Abstract: Three-day-old neonatal rats had their common peroneal nerve crushed 3 mm from the extensor digitorum longus (EDL) muscle. At periodic intervals of 7, 10, 14, 21 and 28 days following nerve injury the EDL muscles were removed, weighed, stained using the silver cholinesterase method and their muscle fibres counted. In these rats during the re-innervation process, the bands of Biingner were absent, some endplates disintegrated and a large proportion of the muscle fibres were lost. This study has shown that interruption of the normal nerve-muscle interaction during the neonatal period is highly detrimental to the subsequent growth and development of …the muscle. Show more

Keywords: Nerve crush, Re-innervation, Motor endplate, Polyneuronal innervation, Muscle

DOI: 10.3233/RNN-1996-10105

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 35-42, 1996

Authors: Kamiguchi, Hiroyuki | Yoshida, Kazunari | Inaba, Makoto | Sasaki, Hikaru | Otani, Mitsuhiro | Toya, Shigeo

Article Type: Research Article

Abstract: Insulin and insulin-like growth factors (IGFs) are the only known trophic factors for pontine cholinergic neurons. The present study revealed that astrocyte-extract pretreated with IL-1β and TNF-α significantly enhanced choline acetyltransferase (ChAT) activity of the pontine neurons in the presence of a supramaximal dose of insulin, while various trophic factors including IGFs failed to increase the ChAT activity under the same culture conditions, suggesting that IL-1β and TNF-α co-operatively enhanced the expression of a novel trophic factor for pontine cholinergic neurons in astrocytes.

Keywords: Astrocyte, effect, InterleukiNeurotrophicn-1β, Tumor necrosis factor-α, Pontine cholinergic neuron, Choline acetyltransferase

DOI: 10.3233/RNN-1996-10106

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 43-47, 1996

Authors: Bartus, Raymond T. | Dean, Reginald L. | Abelleira, Susan | Charles, Vinod | Kordower, Jeffrey H.

Article Type: Research Article

Abstract: While the function and regulation of the low affinity (p75) nerve growth factor (NGF) receptor in the central nervous system (CNS) remains a mystery, one of the more intriguing observations involves its response to injury in the adult rat striatum. Following mechanical injury to the striatum, a re-expression of striatal p75 receptors and mRNA purportedly occurs (apparently mediated by elevations in NGF), thus reversing the natural loss of these phenotypic markers that is known to occur during development. This observation has important implications for understanding both the regulation of NGF neurotrophic activity and the role of the p75 receptor, for …it implies that the presence of this receptor may be required for NGF trophic activity in the CNS. In an effort to gain a greater understanding of the function and regulation of the low affinity p75 NGF receptor, we performed a series of experiments to study the injury-induced, re-expression phenomenon in the striatum. In the first experiment, we duplicated the mechanical, cannula-induced injury used in the original study. In a follow-up study, we exacerbated that injury by infusing quinolinic acid directly into the striatum. In a third study, the mechanical injury was complemented with chronic striatal infusions of NGF. In a final study, we examined striatal tissue from rats who had been protected from striatal quinolinic acid neurotoxicity by administration of NGF. In no instance was the re-expression of p75 striatal receptors observed, despite positive controls for (a) effective neural trauma, confirmed by histologic and immunocytochemical methods, (b) effective antibody staining, confirmed by appropriate basal forebrain p75 immunoreactivity, and (c) effective biological activity of exogenous NGF, confirmed by hypertrophy of choline acetyltransferase (ChAT)-positive striatal neurons and protection of ChAT-positive striatal neurons against excitotoxicity. At least two important conclusions can be drawn from these studies: (1) the presence or induction of low affinity p75 receptors is not necessary, while the presence of constitutive high affinity tropomyosin related kinase (trk) NGF receptors seem sufficient for NGF trophic activity in the CNS, and (2) the variables necessary to induce re-expression of p75 striatal receptors in adult rats have not yet been elucidated and are apparently complex. Show more

Keywords: p75, Nerve growth factor, Receptor regulation, Injury, Trophic response

DOI: 10.3233/RNN-1996-10107

Citation: Restorative Neurology and Neuroscience, vol. 10, no. 1, pp. 49-59, 1996