Opioid and non-opioid mechanisms of stress analgesia: lack of cross-tolerance between stressors.
Qualitatively different analgesic responses can be evoked in rats by exposure to prolonged, intermittent or brief, continuous footshock stress. These two forms of stress analgesia appear to be mediated by opioid and nonopioid pain-inhibitory substrates, respectively. The present study confirms our previous observation that tolerance develops to only the opioid form of stress analgesia and shows that cross-tolerance does not occur between the opioid and nonopioid forms. These data provide further evidence that independent mechanisms underlie opioid and nonopioid stress analgesia.
D000818:Animals; D004597:Electroshock; D008297:Male; D009433:Neural Inhibition; D009619:Nociceptors / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000502:physiology*; D012684:Sensory Thresholds; D013312:Stress, Physiological / Q000503:physiopathology*
D011957:Receptors, Opioid