Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Inhibitory postsynaptic potential
Introduction
Overview
Overview
An Inhibitory Postsynaptic Potential (commonly abbreviated as IPSP) is the change in membrane voltage of a postsynaptic neuron which results from synaptic activation of inhibitory neurotransmitter receptors. The most common inhibitory neurotransmitters in the nervous system are GABA and glycine.
A postsynaptic potential is considered inhibitory when the resulting change in membrane voltage makes it more difficult for the cell to fire an action potential, lowering the firing rate of the neuron. They are the opposite of excitatory postsynaptic potentials (EPSPs), which result from the flow of ions like glutamate into the cell.
Ionic basis of IPSP
Ionic basis of IPSP
At a typical inhibitory synapse the postsynaptic neural membrane permeability increases for positive potassium (K+) ions and/or negative chloride (Cl–) ions but not sodium (Na+) ions. This generally causes an influx of Cl– ions and/or efflux of K+ ions, thereby bringing the membrane potential closer to the equilibrium potential of these ions.
In addition IPSPs may be produced by closure of sodium or calcium channels.