Question

Compare and contrast EPSPs and IPSPs (Make sure to include which ion channels are activated and how, changes in membrane potential as a result of the movement of those ions, as well as a discussion of neurotransmitters)..

Answer 1

Graded potential is caused due to opening of different ligand gated ion channels.postsynaptic potential is one type of graded potential created on the post synaptic membrane.It is of 2 types _EPSP and IPSP.

Ligand is neurotransmitter_binds with specific receptors on the postsynaptic membrane and depending on its nature induces an EPSP &IPSP.

EPSP_excitatory postsynaptic potential,

IPSP_inhibitory postsynaptic potential.

Comparison --

Both are postsynaptic membrane potentials,both are produced due to ligand gated ion channels,l.Both are temprary.Both regulate neurohumeral transmission.

Contrast--1.EPSP--

When a ligand (neurotransmitter) binds with receptor_increase permeability to cations(Na/Ca influx)through fast or slow channels_causes depolarization followed by K+ efflux.These ionic movements are passive as the flow is down the concentration gradient.Takes membrane potential towards the threshold potential.Makes membrane more excited.facilitate further action potential.Neurotransmitters responsible are_Glutamate and aspartate etc.

IPSP--An inhibitory neurotransmitter binds with receptor,increases permeability to anions,so that Cl- ions move in (axonal concentration is lower than its extracellular concentration) and tend to hyperpolarize the membrane_makes membrane less excited_lowers further action potential_takes potential away from threshold potentialNeurotransmitters responsible are_GABA ,glycin etc.