Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cDNA probe to the alpha subunit of the murine acetylcholine receptor was used to demonstrate restriction fragment length polymorphism in an acetylcholine receptor gene in the horse. Three different patterns of polymorphism have been observed with fragment sizes of 4.3 and 2.9 kilobases (kb) (pattern 1), 4.3 and 2.5 kb (pattern 2) and 4.3, 2.9 and 2.5 kb (pattern 1,2). Analysis of a three generation pedigree has suggested that patterns 1 and 2 represent two allelic forms of the gene encoding the alpha subunit of the acetylcholine receptor. These data provide a basis for the examination of the genetic control of neuromuscular function in the horse.
Vet Rec 1987 Apr 11
PMID:Polymorphism of the acetylcholine receptor in the horse. 288 68

The aim of this study was to establish the time scale of developmental changes in innervation of skeletal muscle fibers in man. Specimens of thigh and intercostal muscle from 19 embryos and 18 infants were examined with histological methods which enabled the discrimination between fetal (gamma) and adult (epsilon) types of acetylcholine receptors (AChRs). At 8 weeks of development, AChRs were distributed diffusely in the myotube membranes. Following onset of innervation in approximately the ninth week the length of the AChR positive area diminished and reached its shortest size at the sixteenth developmental week. At the sixteenth and eighteenth week some nerve terminals opposed the muscle membrane outside the AChR positive area. Decrease in the number of nerve terminals, strongly suggesting elimination of polyneuronal innervation, started in the sixteenth week and was completed in the twenty-fifth week. This fetal (gamma) type of AChR could no longer be demonstrated after the thirty-first week. The length of the end-plates as determined by the presence of AChRs increased again in the last week before birth and reached a plateau size by the end of the first year after birth. It is concluded that in man the transition from poly- to mononeuronal innervation takes place between the sixteenth and twenty-fifth weeks of development. The evidence available suggests that the retraction of nerve terminals is preceded by loss of AChRs from the muscle membrane facing the terminals. There is no relationship between retraction of nerve terminals and the switch from fetal to adult type of AChR. The size of the presynaptic apparatus changes little after the first year of life.
Anat Rec 1993 Jul
PMID:Development of innervation of skeletal muscle fibers in man: relation to acetylcholine receptors. 836 59

To morphologically define the aging-related features during muscle reinnervation the spatiotemporal relationships among the major components of the neuromuscular junctions (NMJs) were investigated. A total of 64 rats, 30 adults (4 months old) and 34 aged adults (24 months old), were used. Between 1 and 12 weeks after sciatic nerve-crushing injury, cryosections of skeletal muscle were single or double labeled for S100, a marker of Schwann cells (SCs), for protein gene product 9.5, a neuronal marker, and for alpha-bungarotoxin (alpha-BT), a marker of the acetylcholine receptor site (AChR site), and then observed by confocal laser microscopy. The most obvious age changes were noted: (1) the regenerating SCs and axons were delayed in their arrival at the NMJ, (2) the dimensions of terminal SCs and AChR sites displayed a drastic and long-lasting drop (for terminal SCs, during 1-8 weeks; for AChR sites, during 1-12 weeks); (3) the degree of spatial overlap between AChR sites and terminal SCs was markedly low until 8 weeks post-crush; (4) damage and poor formation in the SCs, terminal axons and AChR sites, together with poor process extension from the terminal SC or terminal axon, were pronounced; (5) persistent aberrant changes, such as multiple innervation and terminal axon sprouting, together with poorly formed collateral innervation, nerve bundles, and NMJs, more frequently occurred in the later reinnervation period. Thus, with aging, regeneration is impaired during the period in which regenerating SC strands and axons extend into NMJs and the subsequent establishment of nerve-muscle contact is in progress. A complex set of morphological abnormalities between or among the TSCs, terminal axons, and AChR sites may be important in slowing of regeneration and reinnervation in aged motor endplates.
Anat Rec 2001 10 01
PMID:The spatiotemporal relationship among Schwann cells, axons and postsynaptic acetylcholine receptor regions during muscle reinnervation in aged rats. 1159 May 95

Skeletal muscle is one of the main targets of the metabolic alterations in diabetes, in which protein synthesis is markedly reduced followed by increased proteolysis. Ultrastructural and functional changes in the presynaptic compartment of the neuromuscular junction (NMJ) have been demonstrated, but little attention has been paid to the proteins in the postsynaptic muscle fiber membrane. In the present work, we studied the changes in acetylcholine receptors (AChRs) and nerve terminal distribution in the NMJ of non-obese diabetic (NOD) mice. The sternomastoid muscles of adult female NOD mice were double-labeled for AChR and nerve terminal observation by fluorescence and reflected light confocal microscopy. In 62.4% of the diabetic endplates, AChR branches broke apart into receptor islands that stained less than in the normal mice. These patches had regular junctional folds. At most of the endplates studied, the nerve terminals colocalized with AChRs, and sprouts were seen in 10% of the diabetic endplates. The intramuscular nerve branches and axons in the nerve to the sternomastoid muscle showed no degenerative disorders. These results suggest that metabolic alterations in the diabetic muscle fiber can affect the distribution and expression of molecules, such as AChRs, in the postsynaptic membrane of the neuromuscular junction.
Anat Rec 2002 Jun 01
PMID:Acetylcholine receptors and nerve terminal distribution at the neuromuscular junction of non-obese diabetic mice. 1199 79

A congenital myasthenic syndrome in Brahman cattle is caused by a homozygous 20 base pair deletion (470del20) in the gene coding for the epsilon subunit of the acetylcholine receptor at the neuromuscular junction. It causes a progressive muscle weakness starting either at birth or within the first month. A PCR-based DNA test, using blood or semen stored on FTA paper, was developed and validated; the test makes it possible to differentiate rapidly and accurately between homozygous wild-type, heterozygous and homozygous affected animals. Preliminary testing of Brahman cattle in South Africa has revealed several carrier animals, some of them influential animals in the breeding population.
Vet Rec
PMID:Congenital myasthenic syndrome of Brahman cattle in South Africa. 1473 94

In normal skeletal muscle, the protein dystrophin is associated with plasma membrane glycoproteins and may be involved in the stabilization of the sarcolemma. Mutant mdx mice are markedly deficient in dystrophin and show muscle fiber necrosis followed by regeneration. Changes in the distribution of acetylcholine receptors (AChRs) have been reported at the neuromuscular junction of mdx mice possibly as a result of alterations in the release or response to neural trophic factors. One such factor is calcitonin gene-related peptide (CGRP), which has been implicated in AChR synthesis and function. In this study, we used rhodamine-alpha-bungarotoxin and anti-CGRP IgG FITC to study AChR and CGRP distribution at the neuromuscular junction of mdx mice. Using laser scanning fluorescence confocal microscopy, it was possible to see that CGRP-like immunoreactivity had a presynaptic distribution, covering the AChRs. Thirty-four percent of dystrophic junctions were found to be labeled with CGRP compared to 80% of control endplates. Since CGRP-positive and -negative fibers showed similar changes in AChR distribution, it is suggested that CGRP is probably not directly involved in the altered pattern of AChR seen in dystrophin-deficient muscle fibers of mdx mice.
Anat Rec A Discov Mol Cell Evol Biol 2004 Aug
PMID:Distribution of calcitonin gene-related peptide at the neuromuscular junction of mdx mice. 1527 51

A retrospective evaluation of 17 dogs treated surgically for idiopathic acquired laryngeal paralysis demonstrated a marked variability in outcome, with many dogs continuing to exhibit weakness and exercise tolerance. In a subsequent prospective study, 22 consecutive affected dogs were tested for neurological deficits by neurological examination, electrodiagnostic evaluation, and blood analysis to measure thyroxine and thyroid-stimulating hormone and to detect any evidence of myasthenia gravis. Clinical neurological deficits and/or electrodiagnostic abnormalities were found in each case. There was limited evidence that specific neurological deficits were associated with a poor prognosis for full recovery of exercise tolerance. None of the dogs was positive for anti-acetylcholine receptor antibodies, and only three showed evidence of thyroid dysfunction.
Vet Rec 2006 Jan 07
PMID:Acquired idiopathic laryngeal paralysis as a prominent feature of generalised neuromuscular disease in 39 dogs. 1640 98

Changes in the distribution of acetylcholine receptors have been reported to occur at the neuromuscular junction of mdx mice and may be a consequence of muscle fiber regeneration rather than the absence of dystrophin. In the present study, we examined whether the nerve terminal determines the fate of acetylcholine receptor distribution in the dystrophic muscle fibers of mdx mice. The left sternomastoid muscle of young (1-month-old) and adult (6-month-old) mdx mice was injected with 60 microl lidocaine hydrochloride to induce muscle degeneration-regeneration. Some mice had their sternomastoid muscle denervated at the time of lidocaine injection. After 10 days of muscle denervation, nerve terminals and acetylcholine receptors were labeled with 4-Di-2-ASP and rhodamine-alpha-bungarotoxin, respectively, for confocal microscopy. In young mdx mice, 75% (n = 137 endplates) of the receptors were distributed in islands. The same was observed in 100% (n = 114 endplates) of the adult junctions. In denervated-regenerated fibers of young mice, the receptors were distributed as branches in 89% of the endplates (n = 90). In denervated-regenerated fibers of adult mice, the receptors were distributed in islands in 100% of the endplates (n = 100). These findings show that nerve-dependent mechanisms are also involved in the changes in receptor distribution in young dystrophic muscles. In older dystrophic muscles, other factors may play a role in receptor distribution.
Anat Rec (Hoboken) 2007 Feb
PMID:Nerve terminal contributes to acetylcholine receptor organization at the dystrophic neuromuscular junction of mdx mice. 1744 Dec 10

Spared extraocular muscles of dystrophic mice are not subjected to regeneration process and can be used to verify whether the lack of dystrophin per se could cause changes in acetylcholine receptor (AChR) distribution. In the present study, rectus and oblique (spared) and retractor bulbi (nonspared) muscles were dissected from adult control (C57Bl/10) and mdx mice. AChRs and nerve terminals were labeled with rhodamine-alpha-bungarotoxin and anti-NF200-IgG-FITC, respectively, and visualized by confocal microscopy. Rectus and oblique muscles presented 0.5% central nucleation, while retractor bulbi had central nucleation in 45% of muscle fibers. In mdx rectus, AChRs were distributed in branches in 99% of the junctions examined (n = 200), similar to that observed for controls. Nerve terminals covered the AChR branches in 100% of the junctions examined. In control retractor bulbi, AChRs were distributed in regular branches. In mdx retractor bulbi, multiple fragmented islands of receptors were seen in 56% of the endplates examined (n = 200). These results suggest that the lack of dystrophin per se does not influence the distribution of acetylcholine receptors at the neuromuscular junction of spared extraocular muscles.
Anat Rec (Hoboken) 2007 Jul
PMID:Acetylcholine receptor organization at the dystrophic extraocular muscle neuromuscular junction. 1749 72