biogenic amine

[bī′ō-jĕnĭk]
n.
  1. Any of a group of naturally occurring, biologically active amines, such as serotonin, that act primarily as neurotransmitters and are capable of affecting mental functioning.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.