TY - GEN ID - cogprints5764 UR - http://cogprints.org/5764/ A1 - Kristal, Dr. Mark B. A1 - Thompson, A. C. A1 - Grishkat, H.L. Y1 - 1985/// N2 - Analgesia, produced by either a morphine injection or footshock, was monitored (using a tail-flick test) in nonpregnant female rats. Analgesia was induced within minutes of having the rats eat on of several substances. When the substance eaten was rat placenta, both the morphine- and shock-induced types of analgesia were significantly grater than in controls that ingested other substances (or nothing). When footshock (hind-paw) was administered in conjunction with the opiate antagonist naltrexone, the analgesia produced was attenuated but detectable; in this case, placenta ingestion did not enhance the analgesia, suggesting that the effect of placenta is specific to opiate-mediated analgesia. It is possible that this enhancement of analgesia is one of the principal benefits to mammalian mothers of ingesting placenta and birth fluids (placentophagia) at delivery. PB - Pergamon Press KW - opiates KW - opioids KW - placentophagia KW - placenta KW - amniotic fluid KW - delivery KW - rat KW - POEF KW - naltrexone KW - analgesia KW - pain KW - tail-flick test KW - footshock KW - afterbirth KW - mammal TI - Placenta ingestion enhances opiate analgesia in rats. SP - 481 AV - public EP - 486 ER -