%A Dr. Mark B. Kristal %A Alexis C. Thompson %A Steve B. Heller %A Dr. Barry R. Komisaruk %J Physiology & Behavior %T Placenta Ingestion Enhances Analgesia Produced by Vaginal/Cervical Stimulation in Rats %X Ingestion of placenta has previously been shown to enhance opiate-mediated analgesia (measured as tail-flick latency) induced either by morphine injection or by footshock. The present study was designed to test whether placenta ingestion would enhance the partly opiate-mediated analgesia produced by vaginal/cervical stimulation. Nulliparous Sprague-Dawley rats were tested for analgesia, using tail-flick latency, during and after vaginal/cervical stimulation; the tests for vaginal/cervical stimulation-induced analgesia were administered both before and after the rats ate placenta or ground beef. Placenta ingestion, but not beef ingestion. significantly heightened vaginal/cervical stimulation-induced analgesia. A subsequent morphine injection provided evidence that, as in a previous report, placenta ingestion, but not beef ingestion, enhanced morphine-induced analgesia. %N 6 %K Placenta, Pain, Opiates, Vaginal stimulation-produced analgesia, Tail-flick test, Afterbirth, Analgesia, Parturition, Placentophagia, VSPA, Vaginal/cervical stimulation, POEF %P 1017-1020 %V 36 %D 1986 %I Pergamon Press %L cogprints6254