Search results for "Innervation"
showing 10 items of 31 documents
Response of abducens internuclear neurons to axotomy in the adult cat
2000
The highly specific projection of abducens internuclear neurons on the medial rectus motoneurons of the oculomotor nucleus constitutes an optimal model for investigating the effects of axotomy in the central nervous system. We have analyzed the morphological changes induced by this lesion on both the cell bodies and the transected axons of abducens internuclear neurons in the adult cat. Axotomy was performed by the transection of the medial longitudinal fascicle. Cell counts of Nissl-stained material and calretinin-immunostained abducens internuclear neurons revealed no cell death by 3 months postaxotomy. Ultrastructural examination of these cells at 6, 14, 24, and 90 days postaxotomy showe…
The role of exercise on peripheral nerve regeneration: from animal model to clinical application
2021
Peripheral nerve injury is a complex condition with a variety of signs and symptoms depending on the severity and nerves involved. Peripheral nerve damage may lead to sensory and motor functions deficits and even lifelong disability, causing important socioeconomic costs worldwide. Despite the increase in knowledge of the mechanisms of injury and regeneration, a full functional recovery is still unsatisfying in the majority of patients. It is well known that exercise promotes physical and psychological well-being, by ameliorating general health. In the last years, there has been a growing interest in evaluating the effects of exercise on the peripheral nervous system. Experimental works wit…
Quantitative image analysis of the chromatolysis in rat facial and hypoglossal motoneurons following axotomy with and without reinnervation.
1996
Image analysis was used to quantify the time course of chromatolysis in regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal nerve suture, or resection of facial and hypoglossal nerves with postoperative survival times of 4 h to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial sections with a VIDASplus image analyzer. In this quantitative study of 149 Wistar rats, alterations of the Nissl substance were measured that were statistically significant but not yet visible to the human eye. Chromatolysis started significantly as early as 8 h and was not fully rev…
Expression Profile of Stress Proteins, Intermediate Filaments, and Adhesion Molecules in Experimentally Denervated and Reinnervated Rat Facial Muscle
1997
The immunohistochemical profiles of ubiquitin, heat shock protein 70, alpha-B-crystallin, desmin, vimentin, neural cell adhesion molecule (N-CAM), and tenascin in rat facial muscle were studied after permanent denervation by transection of the facial plexus on one side and compared with findings after immediate reinnervation by hypoglossal-facial nerve anastomosis subsequent to transection on the contralateral side. Levator labii muscle samples were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery. Normal levator labii muscle fibers showed physiological expression of desmin and alpha-B-crystallin. Denervated rat facial muscle displayed distinct up-regulation of ubiquiti…
Morphology of experimentally denervated and reinnervated rat facial muscle I. Histochemical and histological findings
1994
The morphological changes in rat facial muscles were evaluated after permanent denervation and were compared with findings after immediate reinnervation. Thirty rats underwent transection of the left and right facial nerves immediately followed by hypoglossal-facial nerve anastomosis on the right side (muscular reinnervation) and removal of 8-10 mm of the facial plexus on the left side (permanent muscular denervation). Levator labii muscle samples of both sides were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery and submitted to routine histological and enzyme histochemical staining procedures. In normal levator labii muscles a typical "chessboard" pattern was found, …
Active acetylcholine receptors prevent the atrophy of skeletal muscles and favor reinnervation
2020
Denervation of skeletal muscles induces severe muscle atrophy, which is preceded by cellular alterations such as increased plasma membrane permeability, reduced resting membrane potential and accelerated protein catabolism. The factors that induce these changes remain unknown. Conversely, functional recovery following denervation depends on successful reinnervation. Here, we show that activation of nicotinic acetylcholine receptors (nAChRs) by quantal release of acetylcholine (ACh) from motoneurons is sufficient to prevent changes induced by denervation. Using in vitro assays, ACh and non-hydrolysable ACh analogs repressed the expression of connexin43 and connexin45 hemichannels, which prom…
Absence of an aging-related increase in fiber type grouping in athletes and non-athletes
2020
The ageing-related loss of muscle mass is thought to be partly attributable to motor neuron loss and motor unit remodelling that result in fibre type grouping. We examined fibre type grouping in 19- to 85-year-old athletes and non-athletes and evaluated to which extent any observed grouping is explained by the fibre type composition of the muscle. Since regular physical activity may stimulate reinnervation, we hypothesised that fibre groups are larger in master athletes than in age-matched non-athletes. Fibre type grouping was assessed in m. vastus lateralis biopsies from 22 young (19-27 years) and 35 healthy older (66-82 years) non-athletes, and 14 young (20-29 years), 51 middle-aged (38%6…
Changes of sonographic, magnetic resonance tomographic, electromyographic, and histopathologic findings within a 2-month period of examinations after…
1998
This study compares sonographical, histopathological, magnetic resonance imaging (MRI), and electromyographical (EMG) findings following acute muscle denervation. We performed an experimental denervation of the supraspinatus and infraspinatus muscles on 35 New Zealand white rabbits by segment resection of the suprascapular nerve. The sonographical appearance of the supraspinatus muscle was followed and documented at short time intervals within a 2-month follow-up period. The sonographical, histopathological, and MRI changes due to denervation suggest a regular pattern. Apart from the reduction of the muscle diameter, there were considerable sonographical signs of denervation with an increas…
Treatment with phenoxybenzamine of upper urinary tract complications caused by intravesical obstruction.
1975
Five children in whom reflux and progressive hydronephrosis persisted despite multiple surgical attempts or repair are described. In all cases cystomanometry displayed a marked elevation of the bladder outlet resistance combined with high intravesical pressure values. Therapy with phenoxybenzamine, an alpha-adrenergic blocker, was successful in all cases, restoring a free urine passage of the upper urinary tract and unimpaired voiding preventing urinary diversion which has been considered in some of these children. Although there were no signs of bladder neuropathy, a hyperfunction of the sympathetic innervation as acause for bladder complications is discussed.
Segmental anatomy of the vastus lateralis: guidelines for muscle-sparing flap harvest.
2014
Background: The vastus lateralis muscle is a versatile donor site for pedicled and free flaps that, despite great potential, remains unpopular. Although the muscle is classically described as a single belly, evidence exists for a more complex morphology. The aim of this study was to investigate the segmental anatomy of the vastus lateralis muscle and the feasibility of selective flap harvest. Methods: Ten cadaveric lower limbs were investigated. Muscular partitions were identified according to morphologic architecture, vascular supply, and nerve supply; guidelines for selective flap harvest were described. Twenty-three segmental vastus lateralis (n = 14) or chimeric anterolateral thigh-vast…