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Updated: Oct 13, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Sexual behavior decreases pain sensitivity and stimulated endogenous opioids in male rats
Abstract:
In male rats copulation has antinociceptive effects as measured either by shock-induced vocalizations or hindlimb withdrawal to pinch. Prolonged mating reduces the content of endogenous opioids in midbrain but not in hypothalamus or caudate nucleus. Blockage of opiate receptors with the narcotic antagonist naloxone (4 mg/kg) significantly extends the postejaculatory interval. The results indicate that mating is a biological stimulus for the release of endogenous opoids, possibly to (a) prevent intense sexual stimulation from becoming aversive, and (b) increase its reward value.
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