At a release site and during a release event the postsynapti

At a release site and during a release event, the postsynaptic receptors are saturated. If you increase the amount of neurotransmitter released during a release event what would this do to quantal size?

Solution

Quantal size can be defined as as the synaptic response to the release of neurotransmitter from a single vesicle, which are also known as synaptic vesicles. Acetylcholine binds at the end plate to induce action potential. A temporary depolarization of the end plate occurs by the inflow of positive ions via the ligand gated channels into the postsynaptic cells. With the inflow of positive ions, even after the depolarization threshold is met, or even if the post synaptic receptors are saturated, the voltage gated ion channels open for further depolarization.
As according to Katz experiment, an action potential was formed only after the minimum excitatory postsynaptic potential (e.p.p) was reached, i.e the quanta of Ach molecules was reached.
When excess neurotransmitter was passed, the depolarization rate further increased, increasing the rate of quanta discharge, stored in synaptic vesicles. They showed that the quantal size was uniform even after sending excess Ach. They also showed that the neurotransmitter would be released even without neural stimulus. Also, that the synaptic systems had the presence of the minimum e.p.p. required in order generate stimulus.