Search results for "Alpha-4 beta-2 nicotinic receptor"
showing 10 items of 21 documents
Chapter 9 Nicotinic acetylcholine receptors on hippocampal neurons: cell compartment-specific expression and modulatory control of channel activity
1996
Publisher Summary The neuronal nicotinic acetylcholine receptors (nAChRs) are differentially expressed on the somato-dendritic surface of hippocampal neurons. This chapter demonstrates that various ions and drugs play a crucial role in modulating the activity of neuronal nAChRs. Considering the diversity of the neurotransmitter receptors and their binding sites and the diversity of substances, which can act simultaneously as a primary agonist of one receptor and an allosteric modulator of a different receptor, an enormous variety of combinatorial possibilities can be achieved in the brain giving rise to very complex neuronal networks. The characterization of the diversity of many receptors …
Na+ ions binding to the bradykinin B2 receptor suppress agonist-independent receptor activation.
1996
Control of the balance between receptor activation and inactivation is a prerequisite for seven transmembrane domain (7TM) receptor function. We asked for a mechanism to stabilize the inactive receptor conformation which prevents agonist-independent receptor activation. Na+ ions have reciprocal effects on agonist versus antagonist interaction with various 7TM receptors. To investigate the Na+ dependence of receptor activation we chose the bradykinin B2 receptor as a prototypic 7TM receptor. Decrease of the intracellular Na+ content from 40 mM to 10 mM of COS-1 cells transiently expressing rat B2 receptors activated the B2 receptor in the absence of agonist as shown by a 3-fold increase in t…
Involvement of cholinergic nicotinic receptors in the menthol-induced gastric relaxation.
2014
We have previously demonstrated that menthol reduces murine gastric tone in part through a neural mechanism, involving adrenergic pathways and reduction of ongoing release of acetylcholine from enteric nerves. In the present study we aimed to verify whether the gastric relaxation to menthol may be triggered by interaction with neural receptors or ionic channels proteins, such as transient receptor potential (TRP)-melastatin8 (TRPM8), TRP-ankyrin 1 (TRPA1), 5-hydroxytriptamine 3 (5-HT3) receptor or cholinergic nicotinic receptors. Spontaneous mechanical activity was detected in vitro as changes in intraluminal pressure from isolated mouse stomach. Menthol (0.3-30 mM) induced gastric relaxati…
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…
α7 Nicotinic acetylcholine receptors and modulation of gabaergic synaptic transmission in the hippocampus
2000
The present report provides new findings regarding modulation of gamma-aminobutyric acid (GABA) transmission by alpha7 nicotinic receptor activity in CA1 interneurons of rat hippocampal slices. Recordings were obtained from tight-seal cell-attached patches of the CA1 interneurons, and agonists were delivered to the neurons via a modified U-tube. Application for 6 s of the alpha7 nicotinic receptor-selective agonist choline (or =1 mM) to all CA1 interneurons tested triggered action potentials that were detected as fast current transients. The activity triggered by choline terminated well before the end of the agonist pulse, was blocked by the alpha7 nicotinic receptor antagonist methyllycaco…
Corrigendum to: α-Conotoxins EpI and AuIB switch subtype selectivity and activity in native versus recombinant nicotinic acetylcholine receptors (FEB…
2003
Corrigendum to: K-Conotoxins EpI and AuIB switch subtype selectivity and activity in native versus recombinant nicotinic acetylcholine receptors (FEBS 27779) [FEBS Letters 554 (2003) 219^223]C Annette Nickea;1, Marek Samochockib, Marion L. Loughnana, Paramjit S. Bansala, Alfred Maelickeb, Richard J. Lewisa; aInstitute for Molecular Bioscience, University of Queensland, Brisbane, Qld. 4072, Australia bInstitute for Physiological Chemistry and Pathobiochemistry, University of Mainz, D-55099 Mainz, Germany First published online 24 December 2003
Synthesis and in vitro evaluation of galanthamine derivatives for examination of nicotinic acetylcholine receptor system
2001
ISunmrary: The syntheses and radioactive labeling of several galanthamine derivatives, 6-O-demethyl-6-O-fluoroethylgalanthamine, 10-N-demethyl-lO-Nfluoroethylgalanthamine and N-methylgalanthaminium are reported. First ill vitro evaluations were carried out to determine their properties as allosterically potentiating ligands of nicotinic receptors. N-methylgalanthaminium was found to be a promising candidate for further investigations. The most commonly applied therapeutic approach to balance nicotinic cholinergic deficits in Alzheimer’s disease (AD) patients is the administration of acetylcholinesterase inhibitors (AChE-I) although they have been proven to be of limited therapeutic value [ …
Allosteric modulation of nicotinic acetylcholine receptors as a treatment strategy for Alzheimer's disease
2000
The basic symptoms of Alzheimer's dementia, i.e., a loss in cognitive function, are due to impaired nicotinic cholinergic neurotransmission. To compensate for this impairment by drug treatment, blockers of the acetylcholine-degrading enzyme acetylcholinesterase are applied, even though this approach obviously is prone to many side-effects, including those of muscarinic nature. We have recently described a novel class of nicotinic acetylcholine receptor ligands which, similar to the action of benzodiazepines on GABA(A) receptors, allosterically potentiate submaximal nicotinic responses. The sensitizing effect is a consequence of facilitated channel opening in the presence of allosterically p…
Cellular distribution in the rat telencephalon of mRNAs encoding for the alpha 3 and alpha 4 subunits of the nicotinic acetylcholine receptor.
1995
Pharmacological and electrophysiological studies provide evidence for the involvement of different nicotinic acetylcholine receptor isoforms in rat neocortical and hippocampal signal transduction. Yet, rather little is known on the cellular localization of these isoforms. With the availability of isoform specific nucleic acid probes and sensitive non-isotopic detection systems, nicotinic receptors can be studied on the mRNA level in individual neurons. In this way, we have paradigmatically studied the distribution of the alpha 3 and alpha 4 isoform mRNAs of the nicotinic receptor in the rat telencephalon. In the cerebral cortex, alpha 3 transcripts were mainly located in pyramidal neurons o…
Modulatory control by non-competitive agonists of nicotinic cholinergic neurotransmission in the central nervous system
1995
Abstract Several exogenous and endogenous compounds have been discovered that act on nicotinic acetylcholine receptors as non-competitive agonists (NCA) of low efficacy, and probably also as allosteric regulators of the receptor's sensitivity to acetylcholine. Nicotinic NCAs may be viewed as another facet in the increasingly complex picture of vertebrate brain organization, i.e. they may be part of a higher level ‘chemical’ network that overlays the neuronal network of the CNS. Furthermore, exogenous NCAs may provide a new therapeutic approach to Alzheimer's dementia.