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)

Principal and most active narcotic alkaloid of opium, having powerful analgesic action and some central stimulant action; abuse leads to dependence.

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.

Morphine, narcotic analgesic drug used in medicine in the form of its hydrochloride, sulfate, acetate, and tartrate salts. Morphine was isolated from opium by the German chemist F.W.A. Serturner in about 1804. In its power to reduce the level of physical distress, morphine is among the most...