Psychological or physiological analgesics: A reconciliation

Recently opiate receptors have been discovered in the central nervous system (CNS) which show specificity for opiate drugs as well as for a range of endogenous polypeptides. These endogenous opiates are released during stress and under those conditions have analgesic properties, also their peripheral injection leads to analgesia. In the present paper a common biochemical substrate which involves these polypeptides as an explanation of pharmacological and psychological analgesics is proposed. The evidence for this thesis is reviewed and further experimental tests are suggested.