Metabotropic receptor

A metabotropic receptor is a cell membrane receptor. Main difference to the ionotropic receptor is that located on the intracellular side of the receptor, another signaling cascade, the second messenger pathway followed. This division of the signaling cascade leading to much longer reaction times, which can go up to the order of seconds. Therefore, the metabotropic receptors are slow receptors.

Metabotropic receptors therefore have currents and has no direct influence on the ionic conditions and therefore on the membrane potential. The most water-soluble hormones, and many transmitter in the nervous system using such receptors.

A distinction is made in the second messenger signal transduction between G protein-coupled receptors and enzyme - coupled receptors.

G- protein coupled receptors

At G- protein-coupled receptors signal through the coupling of a G-protein to the intracellular side occurs. This can then, depending on the receptor and G protein- type lead to activation of IP3/DAG-Weges or an increase or decrease in the cAMP level.

Examples include adrenergic receptors, which are activated by catecholamines ( epinephrine and norepinephrine so ) and the muscarinic acetylcholine receptor.

The second messenger then leads into the cell to the desired effect, so for example a calcium influx during IP3/DAG-Weg and thus to a contraction of a ( smooth ) muscle cell or the cAMP pathway to an on and off ( Inter conversation) of enzymes.

Enzyme - coupled receptors

A common variant leads to an autophosphorylation of tyrosine residues on the intracellular side of the receptor (e.g., the insulin receptor) and thus to a signal transmission.

• Signal transduction