Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
5-hydroxytryptamine is a noun meaning "a neurotransmitter involved in e.g. sleep and depression and memory". It carries one recorded sense.
a neurotransmitter involved in e.g. sleep and depression and memory
Definitions, synonyms and semantic relations for 5-hydroxytryptamine come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.