In case of NorEp , there is an active transport system that brings NorEp back into the cytoplasm of the nerve terminal and there is an active transport system that takes NorEp back into synaptic vesicle . These peptides are degraded by peptidases . No reuptake . Demonstrated they are found in vesicles . That Influence ANS 1.
Drug can interfere with synthesis of the neurotransmitter .
For example, on cholinergic side, hemicholinium interferes with synthesis of Ach . Metabolic transformation by same pathway of precursor of the neurotransmitter. The biosynthetic enzyme of catecholamine aren't substrate specific. Methyl norepinephrine gets released due to action potential, but don't have same activity of endogenous neurotransmitter . So false transmitter blocked effect of sympathetic nervous system .