Drug addiction: light at the end of the tunnel.
D000818:Animals; D003214:Conditioning, Classical; D004285:Dogs; D004723:Endorphins; D006801:Humans; D009021:Morphine Dependence / Q000378:metabolism; D009270:Naloxone / Q000494:pharmacology; D010455:Peptides; D011957:Receptors, Opioid / Q000187:drug effects; D019966:Substance-Related Disorders / Q000378:metabolism*
D004723:Endorphins; D010455:Peptides; D011957:Receptors, Opioid; D009270:Naloxone