Subject muscarinic

Traumatic brain injury is the most common cause of death in subjects under the age of 40, and an important risk factor for AD. Loss of hippocampal cells and depletion of ACh and of muscarinic receptors can be attenuated in injured experimental animals, improve blood perfusion in ischemic areas and increase cholinergic transmission in cortex and hippocampus the same mechanism invoked for treatment of VD. 

Scopolamine increases cerebral blood flow to lateral occipital cortex bilaterally and to the left orbitofrontal region (Grasby et al. 1995). Decreases are seen in the right thalamus, precuneus, and lateral premotor areas bilaterally. When normal subjects are chronically administered scopolamine, there is a 12% increase in cerebral blood flow on single photon emission computed tomography (SPECT), but a decrease in cerebral muscarinic binding (Sunderland et al. 1995). On the other hand, acute administration dose-dependently reduces cortical blood flow, which is maximal in frontal cortex (Gitelman and Prohovnik 1992 Prohovnik et al. 1997). 

Fenech AG, Ebejer MJ, Felice AE, Ellul-Micallef R, HaU IP. (2001) Mutation screening of the muscarinic M(2) and M(3) receptor genes in normal and asthmatic subjects. Br J Pharmacol. 133, 43-48. 

Yamamoto T, Yamashita N, Kuwabara M, et al. (2002) Mutation screening of the muscarinic m2 and m3 receptor genes in asthmatics, outgrow subjects, and normal controls. Ann Genet. 45, 109-113. 

R.M. Cohen, T.A. Podruchny, A.L.W. Bokde, R.E. Carson, P. Herscovitch, D.A. Kiesewetter, W.C. Eckelman, T. Sunderland, Higher in vivo muscarinic-2 receptor distribution volumes In ageing subjects with an apolipoprotein E-s4 allele. Synapse... 

Beiko J, Candusso L, Cain DP The effect of nonspatial water maze pretraining in rats subjected to serotonin depletion and muscarinic receptor antagonism a detailed behavioural assessment of spatial performance. Behav Brain Res 88 201-211, 1997... 

Roy-Byrne PP, Uhde TW, Post RM, et al The corticotropin-releasing hormone stimulation test in patients with panic disorder. Am J Psychiatry 143 896-899, 1986 Ruberg M, Ploska F, Javoy-Agid F, et al Muscarinic binding and choline acetyltransferase activity in Parkinsonian subjects with reference to dementia. Brain Res 232 129-139, 1982... 

Some toxins in mushrooms are alkaloids that cause central nervous system effects of narcosis and convulsions. Hallucinations occur in subjects who have eaten mushrooms that contain psilocybin. The toxic alkaloid muscarine is present in some mushrooms. 

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... 

Adverse effects Hi receptor blockers have a low specificity, that is, they interact not only with histamine receptors but also with muscarinic cholinergic receptors, a-adrenergic receptors, and serotonin receptors (see Figure 40.6). The extent of interaction with these receptors and, as a result, the nature of the side effects, vary with the structure of the drug. Some side effects may be undesirable, and others may have therapeutic value. Furthermore, the incidence and severity of adverse reactions varies between individual subjects. 

Betel nut chewing is a common practice in some Asian and Pacific cultures. In subjects with schizophrenia the chewing of betel nut has been preliminarily associated with fewer positive and negative symptoms (Sullivan et al., 2000). Constituents of betel nut have cholinomimetic properties as well as possibly also inhibitory effects on cholinesterase (Gilani et al., 2004). Arecoline, a major component of betel nut, is a known muscarinic and nicotinic agonist (Tripathi, 1983). 

Cannon DM, Carson RE, Nugent AC, Eckelman WC, Kiesewetter DO, et al. 2006. Reduced muscarinic type 2 receptor binding in subjects with bipolar disorder. Arch Gen Psychiatry 63 741-747. 

Crook JM, Tomaskovic-Crook E, Copolov DL, Dean B. 2000. Decreased muscarinic receptor binding in subjects with schizophrenia A study of the human hippocampal formation. Biol Psychiatry 48 381-388. 

Dean B, Crook JM, Opeskin K, Hill C, Keks N, et al. 1996. The density of muscarinic Ml receptors is decreased in the caudate-putamen of subjects with schizophrenia. Mol Psychiatry 1 54-58. 

Dean B, McLeod M, Keriakous D, McKenzie J, Scarr E. 2002. Decreased muscarinic(l) receptors in the dorsolateral prefrontal cortex of subjects with schizophrenia. Mol Psychiatry 7 1083-1091. 

Scarr E, Sundram S, Keriakous D, Dean B. 2007. Altered hippocampal muscarinic M4, but not Ml, receptor expression from subjects with schizophrenia. Biol Psychiatry 61 1161-1170. 

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