Answer:
neurotransmitters
Step-by-step explanation:
varicosities release neurotransmitters when the neuron is stimulated
varicosities are multiple swellings
varicosities are where axons of postganglionic fibers in the autonomic nervous system enter a given tissue
varicosities release neurotransmitters when the neuron is stimulated
varicosities release neurotransmitters along a significant length of the axon
varicosities release neurotransmitters over a large surface area of the effector tissue.
Physiology of the Autonomic Nervous System
NIH