Antibody acetylcholine receptor channel

Autoantibodies are directed against nicotinic acetylcholine receptors in myasthenia gravis, resulting in receptor loss, skeletal muscle paralysis, and dysfunction (100). In addition, antibodies directed against voltage-gated Ca " channels produce similar neuromuscular dysfunction of Lambert-Eaton... 

Acetylcholine receptors in the plasma membrane were initially identified by immunoelectronmicros-copy using anti-acetylcholine receptor antibodies (Klymkowsky and Stroud 1979). Transversing the lipid bilayer is a central channel measured by structural analysis as about 0.7 nm diameter (Kistler et al. 1982), close to the maximum diameter derived from electrophysiological measurements of conductivity of organic cations of various size (Furukawa and Furukawa 1959, Maeno et al. 1977, Huang et al. 1978, Dwyer et al. 1980). Acetylcholine receptors are sevenfold membrane-spanning receptors (Kubo et al. 1986, Hesch 1991). 

Eldefrawi, M. E., D. S. Copio, C. S. Hudson, J. Rash, N. A. Mansour, A. T. Eldefrawi, and E. X. Albuquerque Effects of antibodies to Torpedo acetylcholine receptor on the acetylcholine receptor-ionic channel complex of Torpedo electroplax and rabbit intercostal muscle. Exp. Neurol. 64, 428—444 (1979). 

Acetylcholine has two types of receptors nicotinic ion channel receptors, the receptors inhibited by antibodies in myasthenia gravis, and muscarinic receptors, which exist as a variety of subtypes. The M2 muscarinic receptors activate a Gai/ het-erotrimeric G protein in which release of the Py subunit controls K+ channels and pacemaker activity in the heart. Epinephrine has several types and subtypes of heptahelical receptors p receptors work through a Ga and stimulate adenylyl cyclase 2 receptors in other cells work through a G i protein and inhibit adenylyl cyclase receptors work through Ga, subunits and activate phospholipase Cp. This variety in receptor types allows a messenger to have different actions in different cells. 

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