@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.}
}

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