Amniotic-fluid ingestion enhances the central analgesic effect of morphine.
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.
Di Pirro
J M
JM
Department of Psychology, State University of New York, Buffalo 14260.
Thompson
A C
AC
Kristal
M B
MB
D000653:Amniotic Fluid; D000698:Analgesia; D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D004357:Drug Synergism; D005260:Female; D007276:Injections, Intraventricular; D008845:Microinjections; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology; D010926:Placental Hormones / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats
D010926:Placental Hormones; D009020:Morphine