Initial thermal heat hypoalgesia and delayed hyperalgesia in a murine model of bone cancer pain

Chemical Interactions between Fibrosarcoma Cancer Cells and Sensory Neurons Contribute to Cancer Pain

“…These changes are consistent with the sensitization of C-fibers to heat stimuli in fibrosarcoma tumor-bearing mice (Cain et al, 2001). Moreover, thermal hyperalgesia occurs in a variety of cancer pain models (Menendez et al, 2003;Asai et al, 2005). Whereas increased expression of TRPV1 in DRG neurons has been correlated with thermal hyperalgesia in models of persistent pain (Numazaki and Tominaga, 2004), this channel may also contribute to mechanical hyperalgesia.…”

Acute and chronic administration of the cannabinoid receptor agonist CP 55,940 attenuates tumor-evoked hyperalgesia

“…Using models in which osteolytic fibrosarcoma cells are implanted into the humerus, femur, tibia, or calcaneous bone in mice, investigators have begun to elucidate the pathophysiological processes by which cancer produces pain (Menendez et al, 2003;Schwei et al, 1999;Wacnik et al, 2001;Wacnik et al, 2000). These models have also been used to evaluate novel approaches for treating cancer pain (Honore et al, 2000;Sabino et al, 2002;Sevcik et al, 2005).…”

Advances in the therapy of cancer pain: from novel experimental models to evidence-based treatments

“…In sarcoma-injected mice, El Mouedden and Meert demonstrated that acute treatment with fentanyl, sufentanil, and morphine, were effective in reducing bone cancer pain-related behaviors in a dose-dependent manner (33). Nevertheless, this analgesic response is rather poor compared to the responses in other types of pain (32). Morphine analgesia, also, does not affect limb use during forced ambulation, which is decreased (as expected) in the bone cancer pain model (66).…”

“…It has been thus shown that usually within one week labeled tumor cells are localized nearby the injection site, while after approximately two weeks they have proliferated and occupied the entire intramedullary space within the femoral bone. Later on, these tumor cells break through the bone into the limb soft tissues (2-3 weeks after cell inoculation), producing a macroscopic increase of the limb size from the fourth week (32). Radiologic, histopathologic and macroscopic expansion of the tumor correlates well with behavioral manifestations of pain.…”

“…With the expansion of the tumor, however, thermal hypoalgesia is replaced by thermal hyperalgesia (increased responsiveness to noxious heat) after the fourth week, while initial manifestations of spontaneous pain and mechanical hyperalgesia intensify reaching a peak 3 weeks post-injection. The initial paradoxical thermal hypoalgesia has been attributed to activation of endogenous opioid mechanisms (32). These mediate descending analgesic systems or inhibitory circuits in the dorsal horns.…”