Search results for "Musca"
showing 10 items of 300 documents
Intoxication with a tropenol ester.
2012
BACKGROUND While the effects of medicinal products are investigated in depth before approval, often very little is known about the intermediates occurring during synthesis. The pharmacological properties of these intermediates can differ substantially from those of the end product. AIMS To describe a work accident involving intoxication with such an intermediate, tropenol ester. CASE REPORT A healthy 40-year-old chemical-technical operative erroneously used a scrubbing brush that had just been used to clear up tropenol ester, contaminating his work clothes. Presumably, contact was made with his skin when removing his work clothes later. Shortly thereafter, he developed signs of anticholiner…
Association of a variant in the muscarinic acetylcholine receptor 2 gene (CHRM2 ) with nicotine addiction
2009
Genetic factors contribute to the overall risk of developing nicotine addiction, which is the major cause of preventable deaths in western countries. However, knowledge regarding specific polymorphisms influencing smoking phenotypes remains scarce. In the present study we provide evidence that a common single nucleotide polymorphism (SNP) in the 5′ untranslated region of CHRM2, the gene coding for the muscarinic acetylcholine receptor 2 is associated with nicotine addiction. CHRM2 was defined as a candidate gene for nicotine addiction based on previous evidence that linked variations in CHRM2 to alcohol and drug dependence. A total of more than 5,500 subjects representative of the German po…
Blockade of nicotinic and muscarinic receptors facilitates spontaneous migration of human peripheral granulocytes: failure in cystic fibrosis.
2012
Circulating leucocytes express muscarinic (m) and nicotinic (n) receptors and synthesize acetylcholine (ACh) regulating various cell functions. Leucocytes from patients with cystic fibrosis contain less ACh; therefore it was tested whether the regulation of cellular functions like migration differed from healthy volunteers.Peripheral blood (10-20 ml) was used, leucocytes were isolated by Ficoll® gradient and the commercial MIGRATEST® combined with flow cytometric analysis was applied (pore size 3 μm).In the absence of test substances 4900±1800 (n=10) leucocytes migrated within a time period of 2 h. In the presence of tubocurarine (TC, 30 μM) the cell number increased to 7500±2700 [n=10] cor…
Dysfunction of the non-neuronal cholinergic system in the airways and blood cells of patients with cystic fibrosis.
2007
Abstract The non-neuronal cholinergic system is widely expressed in human airways, skin and immune cells. Choline acetyltransferase (ChAT), acetylcholine and nicotine/muscarine receptors are demonstrated in epithelial surface cells, submucosal glands, airway smooth muscle fibres and immune cells. Moreover, acetylcholine is involved in the regulation of cell functions like proliferation, differentiation, migration, organization of the cytoskeleton, cell–cell contact, secretion and transport of ions and water. Cystic fibrosis (CF), the most frequent genetic disorder, is known to be caused by a mutation of the CF-gene coding for the cystic fibrosis transmembrane regulator protein (CFTR). CFTR …
Cellular Distribution and Expression of Cortical Acetylcholine Receptors in Aging and Alzheimer's Disease
1991
Ligand binding studies show marked reductions of nicotinic, but not of muscarinic binding sites in Alzheimer's disease. Using monoclonal antibodies we studied immunohistochemically the expression of the respective receptor proteins in the frontal cortex of middle-aged (55 +/- 5 yr) controls, age-matched controls (73 +/- 6 yr), and patients with Alzheimer's disease (74 +/- 5 yr). Density of nicotinic cholinoceptive neurons was 8000/mm3 for middle-aged controls and 4000/mm3 for age-matched controls, but only 900/mm3 in Alzheimer's brains (p less than 0.0001). Densities of muscarinic cholinoceptive and of Nissl-stained neurons were not significantly different between the groups, pointing to a …
Inhibition of human detrusor contraction by a urothelium derived factor.
2003
Stimulating muscarinic receptors in pig bladder urothelium causes the release of a diffusable factor that inhibits contractions of the underlying detrusor muscle. We investigated whether the contractions of human detrusor strips elicited by the muscarinic agonist carbachol, electrical field stimulation, KCl or the neurokinin receptor agonist neurokinin A are affected by the urothelium.Paired intact and urothelium denuded muscle strips were placed in modified gassed Tyrode's solution at 37C. Cumulative concentration-response curves to carbachol or KCl were constructed. In other tissues the strips were stimulated electrically (1 to 40 Hz) with trains of square wave pulses 20 seconds in durati…
Glycopyrronium bromide blocks differentially responses mediated by muscarinic receptor subtypes.
1993
To analyse the potency of glycopyrronium bromide in blocking responses mediated via subtypes of muscarinic receptors in vitro, we tried to determine its equilibrium dissociation constants at prejunctional muscarinic receptors inhibiting the twitch response of rabbit vas deferens (presumed M1 type), at M2 (paced at left atria), M3 (guinea pig ileum) muscarinic receptor subtypes and at the muscarinic receptor of the rabbit iris sphincter (not M1-M4, not m5). Glycopyrronium bromide shifted to the right the curve for inhibition of the twitch response induced by the agonist McN-A-343, and the methacholine-induced curves for inhibition of rat atrial contraction, and for tonic contraction of guine…
Agonist potency differentiates G protein activation and Ca2+ signalling by the orexin receptor type 1.
2005
The G protein coupling characteristics of a flag epitope-tagged orexin receptor type 1 (OX1R) was investigated in HEK293 cells. Immunoprecipitation of the OX1R and immunoblotting revealed interactions with Gq/G11 proteins as well as with Gs and Gi proteins. Stimulation with orexin-A did not affect the ability of the OX1R to coprecipitate Gq/G11 proteins, but it robustly elevated the intracellular concentration of Ca2+, [Ca2+]i. No changes in cAMP levels could be detected upon receptor stimulation. To get further insight into the functional correlation of G protein activation and Ca2+ signalling, we used baculovirus transduction to express chimeric G proteins, containing the Galphas protein …
Introductory Lecture: Allosteric Modulation of Torpedo Nicotinic Acetylcholine Receptor Ion Channel Activity by Noncompetitive Agonists
1997
AbstractSimilar to other neuroreceptors of the vertebrate central nervous system, the nicotinic acetylcholine receptor (nAChR) is subject to modulatory control by allosterically acting ligands. Of particular interest in this regard are allosteric ligands that enhance the sensitivity of the receptor to its natural agonist acetylcholine (ACh), as such ligands could be useful as drugs in diseases associated with impaired nicotinic neurotransmission. Here we discuss the action of a novel class of nAChR ligands which act as allosterically potentiating ligands (APL) on the nicotinic responses induced by ACh and competitive agonists. In addition, APLs also act as noncompetitive agonists of very lo…
Acetylcholine and nicotine stimulate the release of granulocyte-macrophage colony stimulating factor from cultured human bronchial epithelial cells.
1998
Primary cultures of human bronchial epithelial cells (HBE-cells) were established to measure granulocyte-macrophage colony stimulating factor (GM-CSF) release. HBE-cells showed a basal GM-CSF release (82+/-20 ng/well/24 h; 30 donors), which was increased by interleukin-1 beta(IL-1beta, 1 ng/ml) by 270%. This effect was blocked by 1 microM dactinomycin or 10 microM cycloheximide, i.e. the stimulatory effect of IL-1beta depended on de-novo synthesis. Histamine (100 microM) and acetylcholine ( 100 nM) stimulated GM-CSF release more than two-fold above the baseline. Nicotine (1 microM) increased GM-CSF release to a similar extent, and this effect was prevented by 30 microM (+)-tubocurarine. The…