Effects of pregabalin and duloxetine on neurotransmitters in the dorsal horn of the spinal cord in a rat model of fibromyalgia.

Dysfunction of the monoamine systems in the nervous system is associated with the clinical symptoms of fibromyalgia. Reserpine-induced myalgia (RIM) rats are a putative model of fibromyalgia in which muscle pressure thresholds and monoamine content is reduced in the brain and spinal cord. We examined the effects of pregabalin and duloxetine, drugs approved for fibromyalgia treatment, on the levels of extracellular neurotransmitters in the dorsal horn of the spinal cord in RIM rats using microdialysis.

An automated method by which effects of compounds on locomotor activity and spontaneous neuropathic pain-specific movements can be simultaneously evaluated in rats with chronic-constriction nerve injury.

Neuropathic pain patients are characterized by evoked pain (hyperalgesia and allodynia) and spontaneous pain, the latter of which is the predominant symptom. In animal models of neuropathic pain, effects of test compounds on spontaneous pain-related behaviors have been evaluated by direct visual observation. In addition, by performing another locomotor activity experiment in normal animals, it is also indispensable to examine whether test compounds cause motor impairment to avoid overestimation of their analgesic activities.