Acetylcholine receptors erythrocyte

The effect of Li+ upon the synthesis and release of acetylcholine in the brain is equivocal Li+ is reported to both inhibit and stimulate the synthesis of acetylcholine (reviewed by Wood et al. [162]). Li+ appears to have no effect on acetyl cholinesterase, the enzyme which catalyzes the hydrolysis of acetylcholine [163]. It has also been observed that the number of acetylcholine receptors in skeletal muscle is decreased by Li+ [164]. In the erythrocytes of patients on Li+, the concentration of choline is at least 10-fold higher than normal and the transport of choline is reduced [165] the effect of Li+ on choline transport in other cells is not known. A Li+-induced inhibition of either choline transport and/or the synthesis of acetylcholine could be responsible for the observed accumulation of choline in erythrocytes. This choline is probably derived from membrane phosphatidylcholine which is reportedly decreased in patients on Li+ [166],... 

Arecaidine (118), 117 and methyl substituted derivatives were tested to determine structural requirements for binding to muscarinic acetylcholine receptors [354]. Arecaidine and 117 stimulated collagen synthesis and increased proliferation of human mucosal fibroblasts [355]. Arecaidine increased micronuclei in mouse polychromatic erythrocytes, was mutagenic in V79 Chinese hamster cells [356], and induced sister-chromatid exchange in mouse bone marrow cells [357],... 

Aiken SP, Horn NM Saunders NR (1992) Effects of amino adds on zinc transport in rat erythrocytes. J Physiol (Lond) 445 69-80 Akabas MH, Stauffer DA, Xu M, Karlin A (1992) Acetylcholine receptor channel structure probed in cysteine-substitution mutants. Science 258 307-310 Alda Torrubia JO, Garay R (1989) Evidence for a major route for zinc uptake in human red blood cells [Zn(HC03)2 Cl] influx through the [Cr/HCOj] anion exchanger. J Cell Physiol 138 316-322... 

Elucidation of the molecular nature of another cholinergic receptor system, the enzyme acetylcholinesterase. is also being attempted through the use of specific, irreversible inhibitors. Belleau and Tanl have recently demonstrated that N,N-dlmethyl-2-chloro-2 phenylethylamine inactivates erythrocyte acetylcholinesterase when acetylcholine is the substrate.. Other workers have provided evidence that the action of this compound involves alkylation at or near the anionic site of the enzyme, rather then at the esteratlc site. Future studies of this system may well be conducted with pure, crystalline enzyme, if a recent report" of the crystallization of acetylcholinesterase from eel electric tissue can be confirmed. 

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