In general terms, the main theme of the research conducted in our laboratory is directed towards a better understanding of the actions of narcotic analgesics and the development of tolerance to and dependence on these drugs. More specifically, our laboratory is concerned with the following aspects of this general research aim: a) Pharmacological characterization of opioid receptors, b) Physiological role of opioid peptides, c) Opioid receptor probes, d) Morphine-PLG interaction.