@misc{cogprints6211, volume = {26}, number = {6}, author = {Jean M. DiPirro and Alexis C. Thompson and Dr. Mark B. Kristal}, title = {Amniotic-Fluid Ingestion Enhances the Central Analgesic Effect of Morphine}, publisher = {Pergamon Press}, journal = {Brain Research Bulletin}, pages = {851--855}, year = {1991}, keywords = {POEF, analgesia, pain, rats, morphine, opioids, placenta, quaternary naltrexone, amniotic fluid, placentophagia, naltrexone methobromide}, url = {http://cogprints.org/6211/}, abstract = {Amniotic fluid and placenta contain a substance (POEF) that when ingested enhances opioid-mediated analgesia produced by several agents (morphine injection, vaginal/cervical stimulation, late pregnancy, footshock), but not that produced by aspirin injection. The present series of experiments employed quaternary naltrexone, an opioid antagonist that does not readily cross the blood-brain barrier, in conjunction with either peripheral or central administration of morphine, to determine whether amniotic-fluid ingestion (and therefore POEF ingestion) enhances opioid-mediated analgesia by affecting the central and/or peripheral actions of morphine. The results suggest that POEF affects only the central analgesic effects of morphine.} }