Retrograde Signaling Occurs When

Retrograde signaling occurs when

A) receptors on the presynaptic membrane are activated resulting in a depolarization of the presynaptic dendrites.
B) acetylcholinesterase levels in a synapse are too high .
C) a postsynaptic cell secretes a signaling molecule that influences the sensitivity of the presynaptic terminal.
D) enzymes responsible for the breakdown of the neurotransmitter at a synapse are not produced in sufficient quantity.
E) none of these.