Indolamines

Indolamines are a family of neurotransmitters that share a common molecular structure (namely, indolamine). A common example of an indolamine is serotonin, which is a neurotransmitter involved in mood and sleep. Another example of an indolamine is melatonin, which regulates the sleep-wake cycle (circadian rhythm) in humans.

In biochemistry, indoleamines are substituted indole compounds that contain an amino group. Examples of indoleamines are the tryptamines, such as 5-hydroxytryptamine (serotonin, 5-HT) and the lysergamides.

Also, histamines are a part of the indolamine family. Histamines are synthesized by the amino acid histidine.

Synthesis
In humans, neurotransmitters in the indolamine family are believed to be produced in the pineal gland. Indolamines are biologically synthesized from the essential amino acid tryptophan.