Involves the production of a generator potential that will trigger the relase of transmitter to a neuron

Involves the production of a receptor potential that will trigger the influx of Ca++ to cause relase of transmitter to a neuron

Involves the activation of a G protein to then produce a generator potential 

Involves the production of a generator potential that will flow along to trigger an AP at a later point on the neuron

Involves the production of a generator potential that will trigger the influx of Ca++ to cause relase of transmitter to a neuron