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metabotropic receptorJoe Segen2016-12-30T21:57:55+00:00
CELL BIOLOGY, METABOLISM
A type of G protein-coupled membrane receptor which is indirectly linked to ion-channels through signal transduction, typically by G protein signalling and enzyme activation. In contrast to ionotropic receptors which form ion channels and when activated, open those channels to ions such as Na+, K+, or Cl–, allowing their flow in or out of cells, metabotropic receptors don’t form channels.
Metabotropic receptor activation triggers intracellular events that lead to the production of second messengers that influence ionotropic receptors and ion channel opening. mGluRs can be subdivided into 3 groups (I-III) according to their sequence similarity, transduction mechanism and pharmacological profile.
Metabotropic receptors. (A) A single protein (monomeric) molecule with seven membrane-spanning domains (I—VII). A neurotransmitter-binding site is located in the extracellular domain (made up of portions of domains II, III, VI, and VII). G-proteins bind to the intracellular loop between domains V and VI and to portions of the C terminus. N and C denote NH2 and COOH terminals, respectively. (B) Heterotrimeric G-proteins consist of three subunits (alpha, beta, and gamma). When guanosine-5′-diphosphate (GDP) is bound to the a-subunit, the a-subunit binds to P- and y-subunits, and an inactive trimer is formed. (C) The steps of a neurotransmitter binding to the metabotropic receptor and the events that follow. GTP = guanosine triphosphate.
Copied verbatim from http://what-when-how.com/neuroscience/neurotransmitters-the-neuron-part-6/
Synonym Metabotropic glutamate receptor