Question

How is the formation of an IPSP different in comparison to an EPSP in the postsynaptic neuron?

Answer 1

Difference between EPSP and IPSP

There are 2 types of neurotransmitters present

Excitatory ---> Glutamate and Aspartate

Inhibitory ----> GABA and Glycine .

**At the postsynaptic membrane, neurotransmitter molecules bind to membrane-bound receptor mole cules with recognition sites specific for that neurotransmitter.

**Binding of the neurotransmitter to the receptor trig-gers a postsynaptic response specific for that recep-tor. These responses can be either excitatory cause by binding of excitatory Glutamate or Aspartate or inhibitory, cause by binding of Inhibitory GABA and Glycine depending on the properties of the receptor.
If receptor stimulation occurs in the postsynaptic membrane it becomes more electrically positive ( more towards action potential)(depolarized). It is an excitatory postsynaptic potential (EPSP).

** If postsynaptic membrane becomes more negative (hyperpolarized), it is an inhibitory post-synaptic potential (IPSP)

**Binding of a neurotransmitter to an excitatory receptor opens a channel (non-voltage gated) that admits Na+ ions or both Na+ and Ca++ ions. Channel opening leads to local depolarization of the postsynaptic plasma membrane, promoting generation of an action potential in postsynaptic neuron .
This excitatory potential in the postsynaptic membrane is known as excitatory postsynaptic potential (EPSP).

**In contrast, binding of a neurotransmitter to an inhibitory receptor on the postsynaptic cell causes opening of K+ (K+ efflux) or, Cl− channels (Cl− influx). The resulting membrane hyperpolarization inhibits generation of an action potential in the postsynaptic cell This inhibitory potential in the postsynaptic mem-brane is known as inhibitory postsynaptic potential (IPSP)