peripheral (autonomic and somatic) nervous systems. In the autonomic (sympathetic and parasympathetic) nervous system, acetylcholine is released from all preganglionic neurons, as well as from postganglionic parasympathetic neurons. Degradation of acetylcholine by the enzyme acetylcholinesterase occurs in the synapse between the presynaptic and postsynaptic membranes. There are two types of pos...

We have isolated a cDNA clone from the nematode Caenorhabditis elegans that encodes a protein of greatest sequence similarity to muscarinic acetylcholine receptors. This gene codes for a polypeptide of 682 amino acids containing seven putative transmembrane domains. The amino acid identities, excluding a highly variable middle portion of the third intracellular loop, to the human m1-m5 receptor...