Serotonin is a neurotransmitter that plays a central role in regulating mood, sleep, appetite and other bodily functions. It was first discovered in 1937 and isolated in 1948. Serotonin is synthesized from the amino acid tryptophan through two enzymatic reactions in serotonergic neurons. It is inactivated through oxidative deamination or conjugation. The gut and blood plasma contain serotonin, while meat, eggs, milk, fish and proteins provide tryptophan, its precursor. Maintaining optimal serotonin levels is important for emotional stability, reducing aggression, and regulating sensory input, sleep and appetite. Deficiencies can result in issues like irritability and sleep disturbances.

1. 1
An introduction to Serotonin,
the chemical of well being
A presentation by
Subarnam Oli
Roll No-57
Central Department of Chemistry,
Tribhuwan University,
Kirtipur, Kathmandu

2. Contents
Introduction
History
Synthesis
Inactivation
Sources
Importance

3. Introduction
Serotonin (5-HT) is a basically a neurotransmitter.
It is believed to play a
central role in
modulation of
vasoconstriction,
anger, aggression,
body temperature,
mood, sleep, sexual
desire, and appetite
as well as stimulation
of vomiting reflex etc.

4. Serotonin can affect the functioning of cardiovascular
system, muscles, the endocrine system.
Serotonin - a chemical manifestation of personality:
High level of serotonin: obsessive-compulsive
disorders e.g. compulsive hand-washing
Low levels of serotonin: depression, suicide.
 Structurally it contains indole ring, hydroxy group and
ethyl amine group being attached to the ring.

5. History
Discovered by:
Vittorio Erspamer (Rome, Italy 1937)
Isolated by:
•Maurice Rapport, Arda Greene and Irvine Page
(Caveland clinic, 1948)
Structure was ilucidated by:
Irvine Page (Director of Division of Research at
Cleveland Clinic 1952)

6. Synthesis
Serotonin is synthesized from the amino acid L-Tryptophan (an
amino acid) which is found profoundly in proteinaceous animal
products, and in plant proteins as well.
Tryptophan is taken up by serotonergic neurons in restricted
brain areas such as the raphe nucleus.

7. Tryptophan hydroxylase, an enzyme catalyses tryptophan, to
forms 5-hydroxytryptophan. This enzyme requires for its
activity the presence of tetrahydrobiopterine as cofactor,
O2 , NADPH2 and a metal, iron or copper.
Decarboxylation of 5-hydroxytryptophan is catalyzed by
Aromatic L-amino acid decarboxylase with pyridoxal-
phosphate as coenzyme.

8. Inactivation
Serotonin is converted into inactive molecules by
biotransformations:
Oxidative deamination of the lateral amino chain by
monoamine oxidase, leading to 5-hydroxy-indol-
acetaldehyde which is then oxidized into 5-hydroxy-indol-
acetic acid (5-HIAA) found in urines in quantities
normally lower than 10 mg/24 hrs.
Conjugation by glucuronic acid or sulfate of the
hydroxyl group in 5-position.

9. Diagram: Main pathway of serotonin catabolism

10. Sources
The serotonin is found abundantly in gut and blood
plasma, but it can not enter the brain.
Meat and banana are the direct sources of serotonin.
The main source of serotonin is L-tryptophan, an
amino acid, which is found in proteins. So proteins are
the main sources of serotonin:
 meat, eggs, milk, fishes
 pulses,
Enough calcium, magnesium and oxygen are also
needed for serotonin production.
Besides these vitamin B6 also promotes its production.

11. Importance of Serotonin
Alone among organs of the body, the gut is able to
mediate reflexes in the absence of input from the brain
or spinal cord. This ability appears to be caused by the
secretion of serotonin by enterochromaffin (EC) cells.
It also regulates bowel movements in the GI tract.
When we have enough Serotonin we have:
Emotional stability
Reduces aggression
Sensory input
Sleep cycle
Appetite control

12. Serotonin Deficiencies result in:
 Irritability
 Irrational emotions
 Sudden unexplained tears
 Sleep disturbances
Optimum serotonin level are also supposed to have
positive impact on learning and cognition.

13. References
1) Gershon M.D.,2000, Curr Opin Gastroenterol, 16(2), 113-
120.
2) Lovinger D.M., 1997, Alcohol Health & Res. World,
21(2), 114-120.
3) http://en.wikipedia.org/wiki/serotonin
4) Motando R.B. et al, 2007, Ame. J Physiol. Gastrointest
liver physicol., 296(4), 963-968.

14. Acknowledgement
I express my deep gratitude to respected
teachers Associate Professor Dr. Susan
Joshi, Associate Professor Dr. Surya Kanta
Kalauni, Associate professor Dr. Bimala
Subba for their constant guide and
support to prepare this presentation. I am
thankful to Central Department of
Chemistry for making this opportunity
available. I am also grateful to my
friends for constant courage, support
and help.

15. 15
THANK YOU FOR KEEPING
PATIENCE & PROVIDING
YOUR VALUABLE TIME
