Search results for "Motoneuron"
showing 10 items of 10 documents
Evidence of resistance training-induced neural adaptation in older adults
2021
The deleterious effects of aging on force production are observable from the age of 40 upwards, depending on the measure. Neural mechanisms contributing to maximum force production and rate of force development have been suggested as descending drive from supraspinal centers, spinal motoneuron excitability, and corticospinal inhibition of descending drive; all of which influence motor unit recruitment and/or firing rate. Resistance-trained Master athletes offer a good source of information regarding the inevitable effects of aging despite the countermeasure of systematic resistance-training. However, most evidence of neural adaptation is derived from longitudinal intervention studies in pre…
The Drosophila Hox gene Ultrabithorax acts both in muscles and motoneurons to orchestrate formation of specific neuromuscular connections
2016
Hox genes are known to specify motoneuron pools in the developing vertebrate spinal cord and to control motoneuronal targeting in several species. However, the mechanisms controlling axial diversification of muscle innervation patterns are still largely unknown. We present data showing that the Drosophila Hox gene Ultrabithorax (Ubx) acts in the late embryo to establish target specificity of ventrally projecting RP motoneurons. In abdominal segments A2 to A7, RP motoneurons innervate the ventrolateral muscles VL1-4, with VL1 and VL2 being innervated in a Wnt4-dependent manner. In Ubx mutants, these motoneurons fail to make correct contacts with muscle VL1, a phenotype partially resembling t…
The Etiology of Muscle Fatigue Differs between Two Electrical Stimulation Protocols
2016
International audience; Purpose: This study aimed at investigating the mechanisms involved in the force reduction induced by two electrical stimulation (ES) protocols that were designed to activate motor units differently. Methods: The triceps surae of 11 healthy subjects (8 men; age, similar to 28 yr) was activated using ES applied over the tibial nerve. Two ES protocols (conventional [CONV]: 20 Hz, 0.05 ms vs wide-pulse high-frequency [WPHF]: 80 Hz, 1 ms) were performed and involved 40 trains (6 s on-6 s off) delivered at an intensity (I-ES) evoking 20% of maximal voluntary contraction. To analyze the mechanical properties of the motor units activated at I-ES, force-frequency relation was…
Structural and functional identification of two distinct inspiratory neuronal populations at the level of the phrenic nucleus in the rat cervical spi…
2018
The diaphragm is driven by phrenic motoneurons that are located in the cervical spinal cord. Although the anatomical location of the phrenic nucleus and the function of phrenic motoneurons at a single cellular level have been extensively analyzed, the spatiotemporal dynamics of phrenic motoneuron group activity have not been fully elucidated. In the present study, we analyzed the functional and structural characteristics of respiratory neuron population in the cervical spinal cord at the level of the phrenic nucleus by voltage imaging, together with histological analysis of neuronal and astrocytic distribution in the cervical spinal cord. We found spatially distinct two cellular populations…
The serum level of free testosterone is reduced in amyotrophic lateral sclerosis
2002
Sporadic amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting upper and lower motoneurons. There is an approximately 2:1 higher incidence of ALS in men compared to women, and this has raised the hypothesis of an involvement of sex hormones in the etiopathogenesis of the disorder. In this work, the serum levels of dehydroepiandrosterone sulphate (DHEAS), 17-betaestradiol, free and total testosterone were measured in 35 patients with defined or probable ALS, according to the El-Escorial/WFN revisited criteria, and compared to those obtained from 57 disease controls, matched for age and gender to the ALS group. We found no differences between ALS cases and …
Clinical features and lifestyle of patients with amyotrophic lateral sclerosis in Campania: brief overview of an Italian database
2012
Background. Physical activity and occupational exposures appeared to play a relevant role in pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease of unknown origin. Materials and methods. We aimed to make an overview of the clinical characteristics and life - style (occupation and sport) of a population of 395 patients with ALS from campania, in southern Italy. Results. ALS onset resulted anticipated of about 11 years in industry workers, whilst the more frequent site of onset among farmers was upper limbs. compared to non-athletes, athletes, particu- larly soccer players, showed a 7 years anticipation of ALS onset, with higher mortality after 5 years. Discussion…
Architecture of cell differentiation, stress-mediated protein expression and transport in iPSC-derived Motor Neurons bearing a pG376D TDP-43 mutation
2020
BACKGROUND AND RATIONALE. ALS is a fatal neurodegenerative disease caused by loss of motoneurons (MNs). Growingevidence suggests that the disease has a strong genetic basis. Up to now, more than 50 ALS-related genes have beenfound. Among these, TARDBP plays a critical role in ALS. Pathogenic mutations in TARDBP gene are found in 1–3% offamilial ALS cases. A few years ago, a novel G376D TARDBP mutation associated to ALS was reported (Conforti et al, 2011). Recently, a verylarge genealogic tree from this G376D family was made (2HE Association, personal communication) leading to a largecollection of DNA, plasma and fibroblasts (FBs) from several family members, both affected and not clinically…
The transcription factor Zfh1 is involved in the regulation of neuropeptide expression and growth of larval neuromuscular junctions in Drosophila mel…
2008
AbstractDifferent aspects of neural development are tightly regulated and the underlying mechanisms have to be transcriptionally well controlled. Here we present evidence that the transcription factor Zfh1, the Drosophila member of the conserved zfh1 gene family, is important for different steps of neuronal differentiation. First, we show that late larval expression of the neuropeptide FMRFamide is dependent on correct levels of Zfh1 and that this regulation is presumably direct via a conserved zfh1 homeodomain binding site in the FMRFamide enhancer. Using MARCM analysis we additionally examined the requirement for Zfh1 during embryonic and larval stages of motoneuron development. We could …
Grp78 overexpression triggers pink1-ip3 r-mediated neuroprotective mitophagy
2021
An experimental model of spinal root avulsion (RA) is useful to study causal molecular programs that drive retrograde neurodegeneration after neuron-target disconnection. This neurode-generative process shares common characteristics with neuronal disease-related processes such as the presence of endoplasmic reticulum (ER) stress and autophagy flux blockage. We previously found that the overexpression of GRP78 promoted motoneuronal neuroprotection after RA. After that, we aimed to unravel the underlying mechanism by carrying out a comparative unbiased proteomic analysis and pharmacological and genetic interventions. Unexpectedly, mitochondrial factors turned out to be most altered when GRP78…
Aging and strength training influence knee extensor intermuscular coherence during low- and high-force isometric contractions
2019
Aging is associated with reduced maximum force production and force steadiness during low-force tasks, but both can be improved by training. Intermuscular coherence measures coupling between two peripheral surface electromyography (EMG) signals in the frequency domain. It is thought to represent the presence of common input to alpha-motoneurons, but the functional meaning of intermuscular coherence, particularly regarding aging and training, remain unclear. This study investigated knee extensor intermuscular coherence in previously sedentary young (18–30 years) and older (67–73 years) subjects before and after a 14-week strength training intervention. YOUNG and OLDER groups performed maximu…