Journal of visualized experiments : JoVE
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Animal models are important tools to study the pathophysiology and pharmacology of neuropathic pain. This manuscript describes the surgical and behavioral procedures to study trigeminal neuropathic pain in rats. To meet the specificity of trigeminal neuropathic pain syndromes, the infraorbital nerve (IoN) is subjected to a chronic constriction injury (CCI) by loosely ligating the nerve. ⋯ During this period, responsiveness to mechanical stimulation of the IoN territory is reduced. This hyporesponsiveness is abruptly replaced by an extreme hyperresponsiveness whereby even very weak stimulus intensities provoke nocifensive behavior (phase 2). The phenomenological similarities between these behavioral alterations and reported signs of facial pain (i.e., responses to noxious stimulation of the face) suggest the presence of dysesthesia/paresthesia and mechanical allodynia in the ligated IoN territory.