Receptor acetyl choline

G protin-coupled receptors Acetyl choline (muscarinic) subunits) 1 3 (1)... 

Acetyl choline is the natural neurotransmitter for the cholinergic receptor. Two distinct receptor subtypes have been characterized based on their binding affinity for either nicotine (189) and (190) or muscarine (191). 

Covalent regulation. Following occupation and activation of the M2 acetyl choline receptors, phospholipase C (PLC), is activated and both inositol (l,4,5)-trisphosphate (IP3), and diacylglycerol (DAG), are formed by hydrolysis of phosphatidylinositol (4,5)-bisphosphate (PIP2). 

As distinct from the acetyl choline receptor of the neuromuscular junction, the acetyl receptors of the viscera are not blocked by nicotine but are blocked by muscarine. Moreover, based on differences in the binding of the muscarinic antagonist, pirenzapine, the muscarinic acetyl choline receptors (mAChRs), are separated into two classes, viz. high affinity mj receptors, and low affinity m2 receptors. The latter predominates in the heart, cerebellum, and smooth muscle broadly. These different receptors mediate quite different actions. 

Nicotine is a component of Nicotiana tabacum, the tobacco plant. It is toxic to many insects because of its action upon the nicotinic receptor of acetyl choline. It has served as a model for a new range of insecticides, the neonicotinoids, which also act upon the nicotinic receptor (Salgado 1999). 

The acetyl choline receptor is a ligand-gated ion channel that allows cations to flow out of the neuron to initiate an action potential during neurotransmission (Fig. 9-6). When the receptor binds acetylcholine, a conformational change of the receptor opens a membrane channel that conducts ions. 

The binding of acetyl choline to the ACETYL CHOLINE RECEPTOR opens a gate that allows cations to pass through the membrane. This is called a ligandgated channel. 

Membrane-associated receptors are linked to transducing proteins (like G-proteins) in the inner portion of the membrane. G-protein coupled receptor (GPCR) families comprise a major class of the receptors that are pharmacologically relevant, such as muscarinic acetyl choline receptors, adrenoceptors, dopamine receptors, serotonine, opiate, peptide hormone, purinerg receptors, and also sensory chemoreceptors. A large variety of subtypes are described in the pharmacological literature. 

G-protein coupled receptor family comprises most well-known cell surface receptors including the major drug targets, as previously stated. Early PAL results have been reviewed in several papers, and book chapters. For opiate, NMDA, sigma, benzodiazepine, GABA, acetyl choline, and adrenerg, serotonine receptors see [52,59,60], and for purinerg, histamine, and dopamine receptors see [61]. 

A series of microcentrifuge tubes is set up, containing the membranes (usually 0.1-0.5 pM in receptor binding sites approximately 0.05-0.25 mg protein/ml) in Torpedo membrane protein and [ H]acetyl-choline concentrations ranging from 0 to 2.0 pM. Nonspecific binding is determined in the presence of excess unlabelled acetylcholine (100 pM-1 mM). 

There are two major subtypes of acetyl choline receptors called ... 

Caulfield MP, Birdsall NJ (1998) International Union of Pharmacology. XVII. Classification of muscarinic acetylcholine receptors. Pharmacol Rev 50 279-90 Caulfield MP, Robbins J, Higashida H, Brown DA (1993) Postsynaptic actions of acetyl-choline the coupling of muscarinic receptor subtypes to neuronal ion channels. Progr Brain... 

The iodinated analogue of A-85380 <1998JME3690>, (S)-5-[123I]iodo-3-(2-azetidinylmethoxy)pyridine 241, is a ligand used for single photon emission computerized tomography (SPECT) imaging of human and nonhuman nicotinic acetyl choline receptors in vivo. 

Acetamiprid (Neonicotinoid) (1992) Nippon soda CH, CN 3 / C = N Cl — V-CKl/ N=/ CH3 Nicotinic acetyl-choline receptor agonist... 

Nitenpyram (Nitromethylene neonicotinoid) (1993) Takeda N —a [Pg.721]

Eldefrawi and Eldefrawi [98] reported the purification of the acetylcholine of Torpedo electroplax on an affinity column consisting of cobra (Naja naja siamensis) toxin coupled to Sepharose 4B. Desorption with 10 mM benzoquinonium produced a protein that bound [ I]a-bungarotoxin but not [ H]acetyl-choline. However, desorption with 1 mM carbamylcholine gave a receptor protein that bound pH]acetylcholine decamethonium, [ H]nicotine [ C]dimethyl-(-l-)-tubocuranrine, and [ I]a bungarotoxin. Schmidt and Raftery [99] also purified acetylcholine receptor, from Narcine, on a N-(e-aminohexanoyl)-3-aminopropyltrimethyl-ammonium bromide-HBr-agarose column. 

It is believed that the weight gain observed in patients being administered typical antipsychotics is related to the antagonist action of these drugs at acetyl choline, serotonin and histamine-1 receptors. 

Pals-Rylaarsdam R, Hosey MM (1997) Two homologous phosphorylation domains differentially contribute to desensitization and internalization of the m2 muscarinic acetyl-choline receptor. J Biol Chem 272 14152-14158... 

The stimulation of the parasympathetic system leads to the opposite effects from those of the sympathetic system. Acetyl choline is released at the target organs and reacts with receptors specific to it and not to noradrenaline. 

Stage 3. The acyl portion of acetyl choline is now covalently bound to the receptor site. Choline leaves the active site and is replaced by water. 

Autoradiographs of Northern blots from unrelated experiments (showing the effects of phorbol ester treatment on the expression of the myogenin gene) were re-labelled to make them appear to have come from different experiments one of them was used in a publication purporting to demonstrate the effect of electrical activity on the expression of genes for subunits of the acetyl choline receptor ... 

For this purpose we have determined whether an alkaloid can displace a specifically bound ligand from a neuroreceptor, such as ot, 0t2 adrenergic receptors, serotonin receptor [5-HT2], and nicotinic and muscarinic acetyl choline receptors (Table 15) obtained from porcine brains [69-72]. In addition, we have determined whether the same alkaloids inhibit acetylcholine esterase, whether they intercalate DNA, inhibit DNA polymerase I, reverse transcriptase, protein biosynthesis and membrane stability [40, 73]. The results can be summarized as follows ... 

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