NCIt definition : 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 exhibits widespread effects including analgesia,
anxiolysis, euphoria, sedation, respiratory depression, and gastrointestinal system
smooth muscle contraction. (NCI04);