Tonic immobility produces hyperalgesia and antagonizes morphine analgesia.
Hyperalgesia was demonstrated during and immediately after termination of tonic immobility in the lizard Anolis carolinensis. Additionally, tonic immobility antagonized morphine-induced analgesia. In conjunction with other research, these data suggest that the response is accompanied by a reduced availability of serotonin, possibly at postsynaptic receptors of raphe neurons.
D000698:Analgesia; D000818:Animals; D001921:Brain / Q000502:physiology; D005071:Evoked Potentials / Q000187:drug effects; D008116:Lizards; D009020:Morphine / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology*; D012149:Restraint, Physical; D012701:Serotonin / Q000502:physiology
D012701:Serotonin; D009020:Morphine