Abstract
Intra-periaqueductal grey (PAG) injection of 1 nmol of oxytocin induced significant increases in hindpaw withdrawal latency (HWL) to thermal and mechanical stimulation in rats. The anti-nociceptive effect of oxytocin was attenuated significantly by subsequent intra-PAG injection of the mu opioid antagonist beta-funaltrexamine (beta-FNA) and the kappa opioid antagonist nor-binaltorphimine (nor-BNI), but not by the delta antagonist naltrindole. The results demonstrated that mu and kappa opioid receptors, not delta receptors, were involved in the oxytocin-induced anti-nociception in PAG of rats.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Analgesics / administration & dosage*
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Animals
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Injections, Intraventricular
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Male
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Narcotic Antagonists / pharmacology
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Oxytocin / administration & dosage*
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Oxytocin / physiology
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Pain Measurement / drug effects
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Periaqueductal Gray / drug effects*
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Periaqueductal Gray / physiology
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Rats
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Rats, Sprague-Dawley
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Receptors, Opioid, kappa / antagonists & inhibitors*
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Receptors, Opioid, kappa / physiology
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Receptors, Opioid, mu / antagonists & inhibitors*
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Receptors, Opioid, mu / physiology
Substances
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Analgesics
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Narcotic Antagonists
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Receptors, Opioid, kappa
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Receptors, Opioid, mu
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Oxytocin