The keys of paradise.

A story of scientific competition and co-operation, the film shows how U.S. and Swedish research into opium addiction led to the discovery of brain receptors for morphine, and the further discovery that the brain contains its own morphine-like chemical, a peptide known as encephalin. Scientists all over the world became involved in this research. A double- blind trial at the Walton Hospital, Liverpool, in which some patients were given a painkiller and others a placebo, followed by a second injection which stopped the effect of the painkiller, found that pain relief continued in the case of the patients who had received the placebo, indicating that the imaginary painkiller caused the brain to produce encephalin. This research may lead to developments in the treatment of schizophrenia, where this is due to a chemical imbalance in the brain.