Morphine sulfate is an alkaloid sulfate salt. It contains a morphine. ChEBI Morphine Sulfate is the sulfate salt of morphine, an opiate alkaloid isolated from the plant Papaver somniferum and produced synthetically. Morphine binds to and activates specific opiate receptors (delta, mu and kappa), each of which are involved in controlling different brain functions. In the central nervous and gastrointestinal systems, this agent has widespread effects including analgesia, anxiolysis, euphoria, sedation, respiratory depression, and gastrointestinal system smooth muscle contraction. NCI Thesaurus (NCIt) The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle. Medical Subject Headings (MeSH)