title: Some thoughts about endogenous opioids and addiction.
mesh_terms: D004361:Drug Tolerance; D004723:Endorphins / Q000502:physiology*; D006801:Humans; D011957:Receptors, Opioid / Q000502:physiology; D019966:Substance-Related Disorders / Q000209:etiology / Q000503:physiopathology*
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid