Acetylcholine Receptor
Proteins in cell membranes with a specific binding site for the neurotransmitter acetylcholine.
Two basic types of A. are distinguished: the nicotinic N-receptor, predominantly postsynaptic on the striated skeletal muscle, on ganglionary synapses, on the adrenal medulla, but also in the CNS. When bound with acetylcholine, its ion channel is opened to sodium ions and the membrane is depolarized by their influx.
The muscarinic M receptor, postsynaptic to parasympathetic nerve endings and in the CNS. When activated by acetylcholine, intracellular messengers (second messengers) are formed. At the heart there is the subtype M2, whose activation by the acetylcholine released by the vagus nerve causes a lowering of the second messenger cAMP (cyclic adenosine monophosphate).