Inhibitory postsynaptic potential

An inhibitory (retardant) postsynaptic potential ( IPSP ) ( English inhibitory postsynaptic potential of Latin inhibere "inhibit") is a local change in the membrane potential of the postsynaptic membrane of animal and human nerve cells , by hyperpolarization of the cell membrane at the synapse causes the excitation of the cell is inhibited and the triggering of action potentials is made more difficult by excitatory postsynaptic potentials (EPSP).

The transmitters of the inhibitory synapses cause a cell response through which channels are opened in the postsynaptic membrane that specifically allow potassium or chloride ions to pass. Opening these ion channels usually results in an outflow of potassium ions from the nerve cell or an influx of chloride ions into the nerve cell. In both cases this leads to an (initially local) hyperpolarization of the postsynaptic membrane or to conditions that make the formation of action potentials difficult or impossible. The postsynaptic receptors can be ionotropic (the receptor is also a channel), but also metabotropic (the receptor is at the beginning of a signal transduction with an effect on ion channels); In the latter case, in particular, it is also possible to close (more precisely: lower the likelihood of being open) of sodium or calcium channels, which directly inhibits EPSPs.

literature

• R. Klinke, St. Silbernagl (ed.): Textbook of Physiology . 4th edition. Thieme-Verlag, 2003, ISBN 3-13-796004-5 .