Effects of Autoantibodies against M2 Muscarinic Acetylcholine Receptors on Rabbit Atria in vivo

Cardiology ◽  
2009 ◽  
Vol 112 (3) ◽  
pp. 180-187 ◽  
Author(s):  
Chang Ming Hong ◽  
Qiang Sun Zheng ◽  
Xiong Tao Liu ◽  
Fu Jun Shang ◽  
Hong Tao Wang ◽  
...  
Keyword(s):  
Acetylcholine Receptors ◽  
Muscarinic Acetylcholine Receptors ◽  
Muscarinic Acetylcholine ◽  
Rabbit Atria

scholarly journals Imaging Muscarinic Cholinergic Receptors in Human Brain in vivo with SPECT, [123I]4-Iododexetimide, and [123I]4-Iodolevetimide

1992 ◽  
Vol 12 (4) ◽  
pp. 562-570 ◽  
Author(s):  
Hans W. Müller-Gärtner ◽  
Alan A. Wilson ◽  
Robert F. Dannals ◽  
Henry N. Wagner ◽  
J. James Frost
Keyword(s):  
Human Brain ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Acetylcholine Receptors ◽  
Brain Regions ◽  
Muscarinic Acetylcholine Receptors ◽  
Emission Computed Tomography ◽  
Nonspecific Binding ◽  
Muscarinic Acetylcholine

A method to image muscarinic acetylcholine receptors (muscarinic receptors) noninvasively in human brain in vivo was developed using [123I]4-iododexetimide ([123I]IDex), [123I]4-iodolevetimide ([123I]ILev), and single photon emission computed tomography (SPECT). [123I]IDex is a high-affinity muscarinic receptor antagonist. [123I]ILev is its pharmacologically inactive enantiomer and measures nonspecific binding of [123I]IDex in vitro. Regional brain activity after tracer injection was measured in four young normal volunteers for 24 h. Regional [123I]IDex and [123I]ILev activities were correlated early after injection, but not after 1.5 h. [123I]IDex activity increased over 7–12 h in neocortex, neostriatum, and thalamus, but decreased immediately after the injection peak in cerebellum. [123I]IDex activity was highest in neostriatum, followed in rank order by neocortex, thalamus, and cerebellum. [123I]IDex activity correlated with muscarinic receptor concentrations in matching brain regions. In contrast, [123I]ILev activity decreased immediately after the injection peak in all brain regions and did not correspond to muscarinic receptor concentrations. [123I]IDex activity in neocortex and neostriatum during equilibrium was six to seven times higher than [123I]ILev activity. The data demonstrate that [123I]IDex binds specifically to muscarinic receptors in vivo, whereas [123I]ILev represents the nonspecific part of [123I]IDex binding. Subtraction of [123I]ILev from [123I]IDex images on a pixel-by-pixel basis therefore reflects specific [123I]IDex binding to muscarinic receptors. Owing to its high specific binding, [123I]IDex has the potential to measure small changes in muscarinic receptor characteristics in vivo with SPECT. The use of stereoisomerism directly to measure nonspecific binding of [123I]IDex in vivo may reduce complexity in modeling approaches to muscarinic acetylcholine receptors in human brain.

Synthesis,18F-Labeling, and Biological Evaluation of Piperidyl and Pyrrolidyl Benzilates as in Vivo Ligands for Muscarinic Acetylcholine Receptors

2000 ◽  
Vol 43 (23) ◽  
pp. 4552-4562 ◽  
Author(s):  
Marc B. Skaddan ◽  
Michael R. Kilbourn ◽  
Scott E. Snyder ◽  
Phil S. Sherman ◽  
Tim J. Desmond ◽  
...  
Keyword(s):  
Acetylcholine Receptors ◽  
Biological Evaluation ◽  
Muscarinic Acetylcholine Receptors ◽  
Muscarinic Acetylcholine

scholarly journals Control of Cardiac Function in vivo with a Light-Regulated Drug

2018 ◽  
Author(s):  
Fabio Riefolo ◽  
Carlo Matera ◽  
Aida Garrido-Charles ◽  
Alexandre M. J. Gomila ◽  
Luca Agnetta ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Mammalian Cells ◽  
Acetylcholine Receptors ◽  
Genetic Manipulation ◽  
Muscarinic Acetylcholine Receptors ◽  
Therapeutic Interventions ◽  
Muscarinic Acetylcholine ◽  
First Time

<p>Remote control of physiological functions with light offers the promise of unveiling their complex spatiotemporal dynamics in vivo, and enabling highly focalized therapeutic interventions with reduced systemic toxicity. Optogenetic methods have been implemented in the heart, but the need of genetic manipulation jeopardizes clinical applicability. This study aims at developing, testing and validating the first light-regulated drug with cardiac effects, in order to avoid the requirement of genetic manipulation offered by optogenetic methods. A M2 muscarinic acetylcholine receptors (mAChRs) light-regulated drug (PAI) was designed, synthesized and pharmacologically characterized. The design was based on the orthosteric mAChRs agonist Iperoxo, an allosteric M2 ligand, and a photoswitchable azobenzene linker. PAI can be reversibly photoisomerized between <i>cis</i> and <i>trans</i> configurations under ultraviolet (UV) and visible light, respectively, and it reversibly photoswitches the activity of M2 muscarinic acetylcholine receptors. We have evaluated <i>in vitro</i> photoresponses using a calcium imaging assay in genetically unmodified receptors overexpressed in mammalian cells. Furthermore, using this new chemical tool, we demonstrate for the first time photoregulation of cardiac function <i>in vivo</i> in wildtype frog tadpoles and in rats with a method that does not require genetic manipulation. Such a new approach may enable enhanced spatial and temporal selectivity for cardiovascular drugs.</p>

scholarly journals Discovery of the first selective M4 muscarinic acetylcholine receptor antagonists with in vivo anti-parkinsonian and anti-dystonic efficacy

2020 ◽  
Author(s):  
Mark S. Moehle ◽  
Aaron M. Bender ◽  
Jonathan W. Dickerson ◽  
Daniel J. Foster ◽  
Yuping Donsante ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Acetylcholine Receptor ◽  
Movement Disorders ◽  
Intracellular Signaling ◽  
Acetylcholine Receptors ◽  
Muscarinic Acetylcholine Receptor ◽  
Muscarinic Acetylcholine Receptors ◽  
Muscarinic Acetylcholine ◽  
Selective Antagonists

AbstractNon-selective antagonists of muscarinic acetylcholine receptors (mAChRs) that broadly inhibit all five mAChR subtypes provide an efficacious treatment for some movement disorders, including Parkinson disease and dystonia. Despite their efficacy in these and other central nervous system disorders, anti-muscarinic therapy has limited utility due to severe adverse effects that often limit their tolerability by patients. Recent advances in understanding the roles that each mAChR subtype plays in disease pathology suggest that highly selective ligands for individual subtypes may underlie the anti-parkinsonian and anti-dystonic efficacy observed with the use of non-selective anti-muscarinic therapeutics. Our recent work has indicated that the M4 muscarinic acetylcholine receptor has several important roles in opposing aberrant neurotransmitter release, intracellular signaling pathways, and brain circuits associated with movement disorders. This raises the possibility that selective antagonists of M4 may recapitulate the efficacy of non-selective anti-muscarinic therapeutics and may decrease or eliminate the adverse effects associated with these drugs. However, this has not been directly tested due to lack of selective antagonists of M4. Here we utilize genetic mAChR knockout animals in combination with non-selective mAChR antagonists to confirm that the M4 receptor underlies the locomotor-stimulating and anti-parkinsonian efficacy in rodent models. We also report the synthesis, discovery, and characterization of the first-in-class selective M4 antagonists VU6013720, VU6021302, and VU6021625 and confirm that these optimized compounds have anti-parkinsonian and anti-dystonic efficacy in pharmacological and genetic models of movement disorders.

scholarly journals Beneficial Metabolic Effects Caused by Persistent Activation of β-Cell M3 Muscarinic Acetylcholine Receptors in Transgenic Mice

Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5185-5194 ◽  
Author(s):  
Dinesh Gautam ◽  
Inigo Ruiz de Azua ◽  
Jian Hua Li ◽  
Jean-Marc Guettier ◽  
Thomas Heard ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Transgenic Mice ◽  
Acetylcholine Receptors ◽  
Muscarinic Acetylcholine Receptors ◽  
Metabolic Effects ◽  
Β Cells ◽  
Β Cell ◽  
Muscarinic Acetylcholine

Previous studies have shown that β-cell M3 muscarinic acetylcholine receptors (M3Rs) play a key role in maintaining blood glucose homeostasis by enhancing glucose-dependent insulin release. In this study, we tested the hypothesis that long-term, persistent activation of β-cell M3Rs can improve glucose tolerance and ameliorate the metabolic deficits associated with the consumption of a high-fat diet. To achieve the selective and persistent activation of β-cell M3Rs in vivo, we generated transgenic mice that expressed the Q490L mutant M3R in their pancreatic β-cells (β-M3-Q490L Tg mice). The Q490L point mutation is known to render the M3R constitutively active. The metabolic phenotypes of the transgenic mice were examined in several in vitro and in vivo metabolic tests. In the presence of 15 mm glucose and the absence of M3R ligands, isolated perifused islets prepared from β-M3-Q490L Tg mice released considerably more insulin than wild-type control islets. This effect could be completely blocked by incubation of the transgenic islets with atropine (10 μm), an inverse muscarinic agonist, indicating that the Q490L mutant M3R exhibited ligand-independent signaling (constitutive activity) in mouse β-cells. In vivo studies showed that β-M3-Q490L Tg mice displayed greatly improved glucose tolerance and increased serum insulin levels as well as resistance to diet-induced glucose intolerance and hyperglycemia. These results suggest that chronic activation of β-cell M3Rs may represent a useful approach to boost insulin output in the long-term treatment of type 2 diabetes.

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