Search results for "Axons"
showing 10 items of 101 documents
The gene encoding ganglioside-induced differentiation-associated protein 1 is mutated in axonal Charcot-Marie-Tooth type 4A disease
2001
We identified three distinct mutations and six mutant alleles in GDAP1 in three families with axonal Charcot-Marie-Tooth (CMT) neuropathy and vocal cord paresis, which were previously linked to the CMT4A locus on chromosome 8q21.1. These results establish the molecular etiology of CMT4A (MIM 214400) and suggest that it may be associated with both axonal and demyelinating phenotypes.
Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera)
1973
1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.
Muscle degeneration in inguinal hernia specimens.
2012
BACKGROUND: There are few articles in the literature reporting the histological changes of groin structures affected by inguinal hernia. A deeper knowledge of this matter could represent an important step forward in the identification of the causes of hernia protrusion. This study aimed to recognise the pathological modifications of muscular structures in autopsy specimens excised from tissues surrounding the hernia orifice. METHODS: Inguinal hernia was identified in 30 autopsied cadavers, which presented different varieties of hernia, including indirect, direct and mixed. Tissue specimens were resected for histological study from structures of the inguinal area surrounding the hernia openi…
Investigations on day-night differences of vesicle densities in synapses of the rat suprachiasmatic nucleus
1990
The present study was conducted to test whether the well-known circadian alterations in physiological and metabolical parameters of the hypothalamic suprachiasmatic nucleus (SCN) are accompanied by day-night differences in the number of vesicles in intrinsic synapses of the nucleus. Two groups of 5 adult male rats each were killed at mid-light or mid-dark, respectively, by perfusion with Karnovsky's fluid. The SCN were removed and processed for routine electron microscopy. In medial parts of the nucleus, synapses were characterized as being of Gray type I (asymmetrical), Gray type II (symmetrical) or of intermediate form, and the vesicles per synaptic profile (VPSP) were counted over a defi…
Origin of impulse initiation in the slowly adapting stretch receptor of the crayfish
1974
Characteristic for the crayfish stretch receptor is a gradual decrease in axon diameter up to a stretch of axon about 350 μm away from the soma-axon border. In response to depolarizing currents applied at different positions along the axon this stretch of axon can be localized as the most excitable membrane region. When depolarizing current steps of 10–25 nA intensity are injected into the soma the first impulse is always triggered in the soma (due to sudden rise in the membrane potential) while the second impulse originates at the axon region of highest escitability. As the intensity of the stimulus is increased the site of impulse initiation along the axon shifts nearer to the receptor so…
The cost of an action potential.
2000
Neuronal modules, or 'cell-assemblies', comprising millions of mutually interconnected cells have been postulated to form the basis of many functions of the brain, such as mood, sleep, hunger, vigilance, and more. Depending on the extent of the module, neurocommunication in cell-assemblies might exceed metabolic resources. A medium-size (10000 neurons) module would require at least 10 J per l of brain, based on a calculated cost of an isolated action potential (AP) of 10(11)-10(12) molecules of ATP per cm(2) of cell membrane, with an absolute minimum of 10(6) ATP at a node of Ranvier. The figure matches the cost of depolarizing the unmyelinated axon of the large monopolar cell in the blowfl…
Lack of GDAP1 induces neuronal calcium and mitochondrial defects in a knockout mouse model of Charcot-Marie-tooth neuropathy
2015
27 páginas, 9 figuras.
Unusual target selectivity of perisomatic inhibitory cells in the hilar region of the rat hippocampus.
2000
Perisomatic inhibitory innervation of all neuron types profoundly affects their firing characteristics and vulnerability. In this study we examined the postsynaptic targets of perisomatic inhibitory cells in the hilar region of the dentate gyrus where the proportion of potential target cells (excitatory mossy cells and inhibitory interneurons) is approximately equal. Both cholecystokinin (CCK)- and parvalbumin-immunoreactive basket cells formed multiple contacts on the somata and proximal dendrites of mossy cells. Unexpectedly, however, perisomatic inhibitory terminals arriving from these cell types largely ignored hilar GABAergic cell populations. Eighty-ninety percent of various GABAergic…
Immunohistochemical analysis of KCNQ2 potassium channels in adult and developing mouse brain
2005
The syndrome of benign familial neonatal convulsions (BFNC) is characterized by seizures starting within the first days of life and disappearing within weeks to months. BFNC is caused by loss-of-function mutations in the potassium channels KCNQ2 and KCNQ3 which can well explain the resulting neuronal hyperexcitability. However, it is not understood why seizures predominantly occur in the neonatal period. A potential explanation might be a change in the expression pattern of these channels during development. We therefore performed an immunohistochemical analysis of mouse brain slices at different stages of postnatal development using an antibody recognizing the C-terminus of the KCNQ2 chann…
Remyelinating strategies in multiple sclerosis.
2014
Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disorder of the CNS characterized by infiltration of immune cells and progressive damage to myelin sheaths and neurons. In recent years, the importance of the neuronal compartment in the early pathology of multiple sclerosis has become increasingly clear. Direct axonal damage within the early stages of inflammation as well as neuronal injury as a result of chronic demyelination are essential factors for the development of long-term disability in patients. Viewing MS as both inflammatory and neurodegenerative has significant implications for treatment, with remyelination of denuded axons to protect neurons from dam…