?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Enhancement+of+Opioid-Mediated+Analgesia%3A+A+Solution+to+the+Enigma+of+Placentophagia&rft.creator=Kristal%2C+Mark+B.&rft.subject=Behavioral+Neuroscience&rft.subject=Animal+Behavior&rft.subject=Behavioral+Biology&rft.subject=Ethology&rft.subject=Evolution&rft.subject=Theoretical+Biology&rft.subject=Comparative+Psychology&rft.subject=Neuroendocrinology&rft.subject=Neuropharmacology&rft.subject=Neurophysiology&rft.subject=Physiological+Psychology&rft.subject=Psychobiology&rft.description=Two+major+consequences+of+placentophagia%2C+the+ingestion+of+afterbirth+materials+that+occurs+usually+during+mammalian+parturition%2C+have+been+uncovered+in+the+past+several+years.+The+first+is+that+increased+contact%2C+associated+with+ingesting+placenta+and+amniotic+fluid+from+the+surface+of+the+young%2C+causes+an+accelerated+onset+of+maternal+behavior+toward+those+young.+The+second%2C+which+probably+has+importance+for+a+broader+range+of+mammalian+taxa+than+the+first%2C+is+that+ingestion+of+afterbirth+materials+produces+enhancement+of+ongoing+opioid-mediated+analgesia.+The+active+substance+in+placenta+and+amniotic+fluid+has+been+named+POEF%2C+for+Placental+Opioid-Enhancing+Factor.+Recent+research+on+both+consequences+is+summarized%2C+with+particular+attention+to+POEF%2C+the+generalizability+of+the+enhancement+phenomenon%2C+its+locus+and+mode+of+action%2C+and+its+significance+for+new+approaches+to+the+management+of+pain+and+addiction.&rft.date=1991&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=text%2Fhtml&rft.identifier=http%3A%2F%2Fcogprints.org%2F180%2F1%2Freview.html&rft.identifier=++Kristal%2C+Mark+B.++(1991)+Enhancement+of+Opioid-Mediated+Analgesia%3A+A+Solution+to+the+Enigma+of+Placentophagia.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F180%2F