Answer:
norepinephrine
Step-by-step explanation:
Most of the postganglionic neurons of the sympathetic division of the autonomic nervous system are adrenergic neurons. This means that these neurons release norepinephrine as a neurotransmitter. Just like acetylcholine, norepinephrine is also stored in synaptic vesicles and is released by exocytosis. Adrenergic receptors present on the postsynaptic neurons of this division serve as binding sites for norepinephrine. The alpha-adrenergic receptors of the postganglionic neurons of sympathetic division are particularly stimulated by norepinephrine.