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The Analgesia-Enhancing Component of Ingested Amniotic Fluid Does Not Affect Nicotine-Induced Antinociception in Naltrexone-Treated Rats

ROBINSON-VANDERWERF, T.M. and DiPirro, Jean M. and Caggiula, Dr. A.R. and Kristal, Dr. Mark B. (1997) The Analgesia-Enhancing Component of Ingested Amniotic Fluid Does Not Affect Nicotine-Induced Antinociception in Naltrexone-Treated Rats. [Journal (Paginated)]

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Abstract

Ingestion of amniotic fluid and placenta by rats has been shown to enhance opioid-mediated antinociception but not affect the nonopioid-mediated antinociception produced by aspirin, suggesting spccificity for opioid-mediated processes. However, enhancement by the active substance(s) in amniotic fluid and placenta1 (POEF, for placental opioid-enhancing factor) of antinociception produced by other nonopioid mechanisms has yet to be examined. The present experiments tested whether ingestion of amniotic fluid enhances the antinociception produced by nicotine injection. In Experiment IA, Enhancement of morphine-mediated antinociception by ingestion of amniotic fluid was demonstrated in a hot-plate assay. In Experiment IB, rats pretreated with naltrexone were given an orogastric infusion of amniotic fluid or control (0.25 ml), then injected with nicotine (0, 0.075, 0.125, or 0.225 mg/kg subcutaneously), then tested for antinociception in a hot-plate assay. Amniotic fluid ingestion did not enhance the antinociception produced by various doses of nicotine. In Experiment 2, rats pretreated with naltrexone were given an orogastric infusion of amniotic fluid (0, 0.125, 0.25, or 0.50 ml) and then injectcd with 0.125 mg/kg nicotine. None of the doses of amniotic fluid enhanced the nicotine-induced antinociception. The findings of these experiments lend support to our contention that the enhancement by POEF of antinociception is specific to opioid-mediated processes.

Item Type:Journal (Paginated)
Keywords:Pain, Analgesia, Antinociception, Amniotic fluid, Placenta, POEF, Nicotine, Hot plate, Rat
Subjects:Psychology > Psychobiology
Psychology > Physiological Psychology
Neuroscience > Behavioral Neuroscience
Neuroscience > Neurochemistry
ID Code:6248
Deposited By:Kristal, Mark B.
Deposited On:02 Nov 2008 10:00
Last Modified:11 Mar 2011 08:57

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