Nicotinic acteylcholine receptor

Scientist regard  the nicotinic acteylcholine receptor as a typical cys-loop receptor, but many types of cys-loop receptors exist.

Members of this superfamily, which includes nicotinic acetylcholine receptors, GABA-A receptors, glycine and 5-HT3 receptors, possess a characteristic loop formed by a disulphide bond between two cysteine residues.

These so-called Cys-loop receptors are proteins that can be found in the cell membrane of neurons and muscle cells (the acetylcholine receptor). They can be activated by transmitters that after binding cause the opening of a channel in the receptor via which ions can flow through the membrane.

The ion flux can cause a neuron to become excited or inhibited. Cys-loop receptors are very important for the function of the brain. For instance, there activity is coupled to transmitter release and thus to the communication of brain cells among each other and of the brain with muscle cells.