n.
Pronunciation: ˌ sir- ə - ' t ō -n ə n, ˌ ser-
Function: noun
Etymology: sero- + ton ic + 1 -in
Date: 1948
: a phenolic amine neurotransmitter C 10 H 12 N 2 O that is a powerful vasoconstrictor and is found especially in the brain, blood serum, and gastric mucous membrane of mammals