<unk>  (molecular formula C8H11NO2; also known as<unk> , and also norsynephrine, para-octopamine and others) is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway.<unk>  is often considered the major "fight-or-flight" neurohormone of invertebrates. Its name derives from the fact that it was first identified in the salivary glands of the<unk> opus. In many types of invertebrates<unk>  is an important neurotransmitter and hormone. In protostomes — arthropods, molluscs, and several types of worms — it substitutes for norephinephrine and performs functions apparently similar to those of norepinephrine in mammals, functions that have been described as mobilizing the body and nervous system for action. In mammals<unk>  is found only in trace amounts, and no biological function has been solidly established for it. It is also found naturally in numerous plants, including bitter orange.<unk>  has been sold under trade names such as Epirenor, Norden, and Norfen for use as a sympathomimetic drug, available by prescription.
Octopamine
Dopamine 
Dopamine
Somatostatin
Growth hormone–releasing hormone
Catecholamine
Prolactin-releasing peptide
Beta-Endorphin