What is the primary neurotransmitter derived from tryptophan?

The primary neurotransmitter derived from tryptophan is serotonin. Tryptophan is an essential amino acid that serves as a precursor for the synthesis of serotonin through a series of enzymatic reactions. Initially, tryptophan is converted into 5-hydroxytryptophan (5-HTP) by the enzyme tryptophan hydroxylase, and subsequently, 5-HTP is decarboxylated to form serotonin (5-hydroxytryptamine or 5-HT).

Serotonin is critically involved in various physiological functions, including mood regulation, sleep-wake cycles, appetite control, and gastrointestinal function. Its deficiency is often linked to mood disorders such as depression and anxiety, making it a significant target in neuropharmacology.

Other neurotransmitters listed, such as dopamine and norepinephrine, derive from different amino acids; dopamine is synthesized from tyrosine, while norepinephrine is a direct derivative of dopamine. Histamine is synthesized from the amino acid histidine. Therefore, understanding the specific pathways through which these neurotransmitters are formed clarifies why serotonin, derived specifically from tryptophan, is the correct answer.