Biochemical studies of opiate action

The opium poppy has for centuries been associated with the deadening of pain and production of euphoria. The pharmacologically active agent was identified as morphine, the major alkaloid component of opium. Single doses of morphine relieve all but the most severe pain. Unfortunately, morphine does cause other effects such as constipation, hypotension and respiratory depression. The most serious disadvantage, however, is the onset of tolerance and physical dependence after prolonged administration. This leads to the social problem of addiction. Particularly important in this respect is the abused narcotic, heroin. [Continues.