Muscarinic acetylcholine receptors mAChRs

Muscarinic acetylcholine receptors (mAChRs) form a class of cell surface receptors that are activated upon binding of the neurotransmitter, acetylcholine. Structurally and functionally, mAChRs are prototypical members of the superfamily of G protein-coupled receptors. Following acetylcholine binding, the activated mAChRs interact with distinct classes of heterotrimeric G proteins resulting in the activation or inhibition of distinct downstream signaling cascades. 

It has been known for some time that the enteric nervous system does not simply regulate smooth muscle contraction, but is intimately involved in the control of transport processes in enterocytes. Nerve fibres in the mucosa terminate subjacent to the basement membrane of epithelial and entero-endocrine cells, on which muscarinic acetylcholine receptors (mAChRs)... 

Miyamoto et al. have also demonstrated in the dry skin and itch mouse model (water + acetone ether treated) that the scratching response can be inhibited by the use of atropine, a nonspecific muscarinic acetylcholine receptor (mAChR) antagonist, and 4-diphenyl-acetoxy-N-methyl-piperidine (4-DAMP), an M3 mAChR antagonist.32 They further showed that Mi and M2 mAChR antagonist were not able to inhibit the scratch response. This report suggests the role of acetylcholine, and the M3 specific receptor as a potential player in dry-skin-associated pruritus. In addition, skin biopsies in human subjects with atopic dermatitis were found to have increased levels of acetylcholine compared with normal controls, which suggests that abnormal concentrations of neurotransmitters may also be involved in itch secondary to xeroderma.33... 

An important advance in PET related chemistry was achieved by Welch and Wolf and their coworkers,388,389 who were able to use the K18F/2.2.2-kryptofix combination for aromatic nucleophilic substitution of activated aromatic rings, which could serve as starting materials for more complex products. Welch and coworkers started with nitrobenzalde-hyde, which was converted to [18F]fluorobenzaldehyde making eventually [18F]fluorodexetimide 62 (equation 224) which acts as a muscarinic acetylcholine receptor (mAchR) antagonist. It was used for PET brain studies since acetylcholine receptors are... 

Some studies have also shown that retrograde endocannabinoid signalling can also be induced by postsynaptic activation of metabotropic glutamatergic receptors (mGluRs) and muscarinic acetylcholine receptors (mAChRs). Like fhe... 

Table 4. Examples of Alkaloids Which Bind to Muscarinic Acetylcholine Receptors (mAChR) (Natural Ligand Acetylcholine)...

Muscarinic acetylcholine receptors (mAChRs) belong to the G protein-coupled receptor (GPCR) family. To date, five distinct subtypes of mAChRs (M1-M5) have been cloned and seqnenced. They share common orthosteric ligand-binding sites... 

Chronic inflammation is considered to be a contributing factor in AD. Besides the low ACh levels in the brains of AD patients, decreased number of nicotinic (nAChR) and muscarinic acetylcholine receptors (mAChR) has been detected in AD patients brains as well as in experimental AD animals [24, 27]. In a recent publication, hupA has been shown to reduce both acute and chronic cerebral inflammation in rats, by a mechanism that is believed to be mediated through the nAChR [11]. 

Macfadyena unguis-cati, 4094 mAChR. See Muscarinic acetylcholine receptors (mAChR)... 

BZ accumulates in the cerebrum following an IV injection in rats (Sawada et al., 1990). It is highly lipophilic and has a high degree of plasma protein and red cell binding. Steady sfafe was reached in the cortex and caudate within 1-5 min. Binding to high-affinity muscarinic acetylcholine receptors (mAChRs) is essentially irreversible for the first 6h. 

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