Effect of colchicine on transport of amine storage granules in sympathetic nerves of rat
ABSTRACT Local application of colchicine to adrenergic ganglia and axons seems to interrupt the fast proximo-distal transport of amine storage granules. This effect may be due to destruction of neurotubules, which possibly take part in granular transport.
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ABSTRACT: The aging brain is characterized by selective neurochemical changes involving several neural populations. A deficit in the cholinergic system of the basal forebrain is thought to contribute to the development of cognitive symptoms of dementia. Attempts to prevent age-associated cholinergic vulnerability and deterioration therefore represent a crucial point for pharmacotherapy in the elderly. In this paper we provide evidence for the protective effect of nicergoline (Sermion®) on the degeneration of cholinergic neurons induced by nerve growth factor deprivation. Nerve growth factor deprivation was induced by colchicine administration in rats 13 and 18 months old. Colchicine induces a rapid and substantial down-regulation of choline acetyltransferase messenger RNA level in the basal forebrain in untreated adult, middle-aged and old rats. Colchicine failed to cause these effects in old rats treated for 120 days with nicergoline 10 mg/kg/day, orally. Moreover, a concomitant increase of both nerve growth factor and brain-derived neurotrophic factor content was measured in the basal forebrain of old, nicergoline-treated rats. Additionally, the level of messenger RNA for the brain isoform of nitric oxide synthase in neurons of the basal forebrain was also increased in these animals.Based on the present findings, nicergoline proved to be an effective drug for preventing neuronal vulnerability due to experimentally induced nerve growth factor deprivation.Neuroscience 02/2002; DOI:10.1016/S0306-4522(01)00470-5 · 3.33 Impact Factor
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ABSTRACT: By using immunofluorescence methodology, extensive galanin (GAL) and GAL message-associated peptide (GMAP)-positive terminal networks were observed in the hippocampal formation. The majority of the GAL/GMAP fibers were dopamine β-hydroxylase- (DBH) positive, that is, they were noradrenergic. This finding was established with GAL/GMAP-DBH double-staining and with 6-hydroxy-dopamine treatment, which totally abolished all fibers in which GAL/GMAP and DBH coexisted. Also, reserpine treatment caused a marked depletion of GAL. No evidence for GAL/GMAP coexistence with 5-hydroxytryptamine was obtained. In the ventral hippocampus, GAL/GMAP-, DBH-negative fibers were seen in the stratum oriens, the anterior stratum radiatum, along the granule cell layer and in the strata oriens and alveus. In the locus coeruleus (LC), around 80% of the GMAP-positive neurons contained neuropeptide tyrosine (NPY), and about 40% of the NPY-positive neurons expressed GMAP. GAL-R1 receptor mRNA was expressed in Barrington's nucleus (close to the LC), but was not detected in the hippocampal formation/dorsal cortical areas. GAL-R2 receptor mRNA was found in the granule cell layer in the dentate gyrus.The present results show that most, but not all, immunohistochemically detectable GAL/GMAP in the hippocampal formation/dorsal cortex is present in noradrenergic nerve terminals originating in the LC, which has a robust GAL/GMAP synthesis. The functional role of GAL may be related to noradrenaline, possibly by a presynaptic action. However, the presence of GAL in other systems and of GAL-R2 receptor mRNA in granule cells also indicates other targets. J. Comp. Neurol. 392:227–251, 1998. © 1998 Wiley-Liss, Inc.The Journal of Comparative Neurology 03/1998; 392(2):227 - 251. DOI:10.1002/(SICI)1096-9861(19980309)392:2<227::AID-CNE6>3.0.CO;2-4 · 3.51 Impact Factor
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ABSTRACT: Ultrastructural studies of single and serial sections of bullfrog olfactory axons showed that smooth endoplasmic reticulum (SER) tubules, which usually appear as single profiles in cross-sections of axons, are continuous over considerable distances, but that discontinuities do exist. Computer-assisted three-dimensional reconstruction of portions of axons indicated that the SER tubules show considerable variation in the volume of the cisternal space along the tubule, which often follows a tortuous path. Some branching and anastomosing appears to occur, and electron-dense material was present in the cisternal space of some tubules. SER tubules are often bridged to neurofilaments and less often to microtubules. The usual two to three microtubules in the axoplasm form a domain which is characterized by a clear area, or zone of exclusion, around the microtubules. Ultrastructural cytochemistry was used to demonstrate that SER tubules actively sequester Ca. The electron-dense product (calcium oxalate) was uniformly and specifically associated with the SER of axons at both proximal (closest to the perikarya in the olfactory epithelium) and distal (closest to the olfactory lobe of the brain) ends of the olfactory nerve. It is concluded that the primary function of SER tubules in these axons is to serve in the regulation of Ca in the axoplasm, probably to facilitate fast axoplasmic transport, and that a secondary function may be the translocation of material in the cisternal space. The observations are discussed as they may relate to the "microstream" hypothesis of axoplasmic transport, and it is argued that fast transport occurs through the zone of exclusion associated with the microtubule domain(s) of axons.The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 12/1985; 5(11):3047-60. · 6.75 Impact Factor