I am trying to understand the mechanisms underlying action potential generation on the cellular level.
Typically, there is an emphasis on voltage-dependent permeability changes of Potassium (K+) and Sodium (Na+) channels which lead to the respective changes of the membrane potential.
Also typically, synapses in the brain are chemical synapses (in contrast to the smaller fraction of electrical synapses, e.g. in the hippocampus, which make use of gap junctions for signal transmission).
My confusion is now this: Chemical synapses depend on neurotransmitters to trigger permeability changes. The canonical explanation of action potentials is with reference to voltage-gated channels -- how do these two things go together?