A Primer on Opioids/Opiates Richard L. Bell, Ph.D. Associate Professor Department of Psychiatry Indiana University School of Medicine ***Earlier in the literature “opiates” referred to exogenous ligands for opioid receptors, whereas “opioids” referred to endogenous ligands for opioid receptors

Opioid Agonists Exogenous opioids Endogenous opioids Mu agonist (Ag) morphine, fentanyl, methadone, codeine, hydrocodone, oxycodone, hydromorphone, levorphanol, meperidine, oxymorphone, tramadol, propoxyphene, sufentanil, remifentanil Mu pAg pentazocine, butorphanol, nalbuphine, buprenorphine Delta receptor morphine, fentanyl Kappa receptor morphine, fentanyl, pentazocine, butorphanol, nalbuphine Naloxone mu, delta, and kappa antagonist Naltrexone mu, delta, and kappa antagonist Endogenous opioids Mu receptor beta-endorphin, endomorphin Delta receptor leu-encephalin, met-encephalin, beta-endorphin Kappa receptor dynorphin

Befort 2015 Front Pharmacol

Delta receptor location and emotional/cognitive/physiological function Chung and Kieffer 2013 Pharmacol Ther

Mu- and delta-receptor co-expression and functional areas of the brain (red reflects only mu-receptor) Erbs et al 2015 Brain Struct Funct

Lalanne et al 2014 Front Psychiatry

Yijun-Cui et al 2014 Nature Neuroscience

Navratilova and Porreca 2014 Nature Neuroscience

Opioid Treatments for Addiction

Transcranial Stimulation decreases mu-opioid receptor binding.

National Institute on Drug Abuse; Center for Disease Control and Prevention