Search results for "nerve"
showing 10 items of 1683 documents
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…
Nitric oxide synthase neurons in the rodent spinal cord: distribution, relation to Substance P fibers, and effects of dorsal rhizotomy.
2001
The indirect immunofluorescent method was employed to investigate the distribution of neuronal nitric oxide synthase-like immunoreactivity(nNOS-LI) in the spinal cord of the golden hamster and to compare it to data obtained from rats. Immunoreactive neurons were found throughout the cervico-sacral extent in the dorsal horn (mainly in laminae I-III) and in the preganglionic autonomic regions, i.e., the sympathetic intermediolateral nucleus (IML), lateral funicle (LF), intercalated region (IC), the area surrounding the central canal (CA), and the sacral preganglionic parasympathetic cell group. While the distribution of immunoreactive cells was generally similar in both species, some differen…
Nitric oxide synthase-immunoreactive vagal afferent fibers in rat superior cervical ganglia
1995
Abstract Chronic (5–14 days) preganglionic denervation of the rat superior cervical ganglia by sectioning the cervical sympathetic trunk resulted in a time-related partial or complete loss of nitric oxide synthase (isoform I)-immunoreactive fibers and terminals surrounding many sympathetic ganglionic neurons. Unexpectedly, denervation unmasked many varicose nitric oxide synthase-immunoreactive fibers, some of which could be traced the entire length of the superior cervical ganglia. Injection of the retrograde tracer Fluorogold into the superior cervical ganglia labeled a population of nodose ganglion cells and of dorsal root ganglion cells from C8 to T3 segments. When the same sections were…
Surface Electromyography Reliably Records Electrophysiologically Evoked Internal Anal Sphincter Activity: A More Minimally Invasive Approach for Moni…
2016
<b><i>Background:</i></b> Even in the case of minimally invasive pelvic surgery, sparing of the autonomic nerve supply is a prerequisite for maintaining anal sphincter function. Internal anal sphincter (IAS) innervation could be electrophysiologically identified based on processed electromyographic (EMG) recordings with conventional bipolar needle electrodes (NE). This experimental study aimed for the development of a minimally invasive approach via intra-anal surface EMG for recordings of evoked IAS activity. <b><i>Methods:</i></b> Six male pigs underwent nerve-sparing low anterior rectal resection. Electric autonomic nerve stimulations were …
Role of calcineurin in Ca2+-induced release of catecholamines and neuropeptides
1998
Neurotransmission requires rapid docking, fusion, and recycling of neurotransmitter vesicles. Several of the proteins involved in this complex Ca2+-regulated mechanism have been identified as substrates for protein kinases and phosphatases, e.g., the synapsins, synaptotagmin, rabphilin3A, synaptobrevin, munc18, MARCKS, dynamin I, and B-50/GAP-43. So far most attention has focused on the role of kinases in the release processes, but recent evidence indicates that phosphatases may be as important. Therefore, we investigated the role of the Ca2+/calmodulin-dependent protein phosphatase calcineurin in exocytosis and subsequent vesicle recycling. Calcineurin-neutralizing antibodies, which blocke…
Investigations of the sensory blockade effect of perineurally injected ethanol on the tail nerve of the mouse.
1976
The effect of an alcohol block on the conduction of sensory stimuli in the tail nerve of the mouse was investigated using the perineural injection of solutions of ethanol (35, 40 and 45%). One hundred and fifty white mice of either sex were given 2 X 0.03 ml of the relevant alcohol solution into both sides of the tail. Before and after the injections repeated sensory conduction measurements were made using the rat tail method. Using 35% ethanol a temporary block of pain conduction could be achieved in both sexes. By increasing the concentration to 40 or 45%, a prolongation of the blocking effect and an increase in the accompanying increase of the pain threshold was observed in some animals.…
Thyroid hormone deficiency disrupts rat eye neurodevelopment
2010
Clinical and experimental studies have highlighted the role played by thyroid hormones (TH) in neural and neuro-sensorial development. However, knowledge on TH mechanisms on the developing visual system is still incomplete. To uncover TH actions on the eyes and vision we carried out a microscopical study on the role of TH in the developing retina and optic nerve, in a rat model of controlled TH deficiency (THD). Morphometric and stereological analyses of the retina and optic nerve showed a reduction in the volume of the eye (p<0.001) and optic nerve cross-sectional area (p<0.001), and thinning of the retinal layers (p<0.001). Glial development and myelination was significantly delayed in th…
A critical period for experience-dependent remodeling of adult-born neuron connectivity.
2015
Neurogenesis in the dentate gyrus (DG) of the adult hippocampus is a process regulated by experience. To understand whether experience also modifies the connectivity of new neurons, we systematically investigated changes in their innervation following environmental enrichment (EE). We found that EE exposure between 2-6 weeks following neuron birth, rather than merely increasing the number of new neurons, profoundly affected their pattern of monosynaptic inputs. Both local innervation by interneurons and to even greater degree long-distance innervation by cortical neurons were markedly enhanced. Furthermore, following EE, new neurons received inputs from CA3 and CA1 inhibitory neurons that w…
Neuroprotective potential of erythropoietin and darbepoetin alfa in an experimental model of sciatic nerve injury. Laboratory investigation.
2007
Object The objectives of this study were to examine whether the systemic administration of recombinant human erythropoietin (rHuEPO) and its long-lasting derivative darbepoetin alfa expedited functional recovery in a rat model of sciatic nerve injury, and to compare the effects of these agents in the model. Methods Thirty male Sprague–Dawley rats received a crush injury to the left sciatic nerve and subsequently underwent either placebo treatment, daily injections of rHuEPO, or weekly injections of darbepoetin alfa. Results Both rHuEPO and darbepoetin alfa were effective in reducing neurological impairment and improving compound muscle action potentials following nerve injury. Darbepoetin …
Intraoral electrostimulator for xerostomia relief: a long-term, multicenter, open-label, uncontrolled, clinical trial
2012
Objective A previous sham-controlled multinational study demonstrated the short-term efficacy and safety for xerostomia treatment of an intraoral device that delivers electrostimulation to the lingual nerve. The objective of this study was to test the hypothesis that those beneficial effects would be sustained over an 11-month period. Study Design The device was tested on a mixed sample of 94 patients with xerostomia in an open-label, uncontrolled, prospective multicenter trial. Statutory outcome assessments were done at 5th, 8th, and 11th months and analyzed by multiple comparisons. Results Improvements achieved at month 5 from baseline were sustained throughout the follow-up period for th…