Synaptic transmission is a multi-stage process each with its own kinetics

After the terminal is depolarized, vesicles have to be recycled and filled with transmitter

After the terminal is depolarized, microtubules have to release filled vesicles to docking proteins

Vesicles take time to move to the active zone when the terminal is depolarized

Vesicles take time to be filled when the terminal is depolarized

After fusion with the terminal membrane and release of neurotransmitter, the vesicle membrane is recycled within the terminal.

Vesicle fusion with the terminal membrane can occur only in the region of the active zones.

Only vesicles bound to docking proteins can fuse with the pre-synaptic membrane.

Voltage-gated calcium channels are found across the entire surface of the terminal.

Calcium entry into the terminal occurs only through voltage-gated channels.

To allow control through pre-synaptic receptors

To create a mechanism for termiantion of transmitter binding to post-synaptic receptors

To allow binding to post-synaptic receptors

To allow regulated release of transmitter

To allow regulated release of transmitter to be terminated

An increase in [Ca++] in the terminal

Binding of vesicles to docking proteins

 Inhibition of voltage-gated Ca++ channels

 An increase in the [K+] in the terminal

A decrease in [Ca++] in the terminal

Transmission using peptides is faster than when using non-peptide transmitters

Peptidergic transmission is less dependent on Ca⁺⁺

Peptides are synthesized in the cell body whereas non-peptides are synthesized in the terminal

Peptidergic transmission involves the use of microtubules while non-peptide transmission depends on active zones

Peptides are not stored in vesicles as are non-peptide transmitters

Modulation of the influx of K⁺

Modulation of Ca⁺⁺ entry into the pre-synaptic terminal

Modulation of the flow of ions compared to the flow at rest

Modulation of the terminal depolarization

Modulation of the efflux of Na⁺

the amount of K+ leaving the cell

the amount of Cl- entering the cell AND the amount of K+ leaving the cell

the amount of Na+ and Ca++ leaving the cell

the amount of Cl- entering the cell AND the amount of Na+ leaving the cell

the amount of Cl- entering the cell and Na+ leaving the cell