[New knowledge in the biochemistry and function of ion channels]

Newer realizations concerning the structure and the function of various forms of ion canals are described. The Na- and K-ion channels occur in a particularly great number in certain membrane regions of nerve cells and muscle fibres and cause the formation and distribution of bioelectric signals. In the K-ion channels various types with different function appear in single cell forms. The Ca-ion channels play a role in the regulation of the release of neurotransmitters and of peptide hormones from granules as well as in the contraction of the heart and skeletal musculature. The ion channels are constructed by various proteins, in certain sections they specifically bind certain toxins and medicaments. The acetyl choline receptor consists of 5 subunits and acts as ion channels for Na- and K-ions; this is opened for a short time after binding of 2 molecules of acetyl choline to the alpha-subunits. The properties of the channel proteins are influenced by phosphorylation.