BACKGROUND Neuropathic pain patients have described experiencing unprovoked, intermittent pain attacks with shooting, stabbing, and burning qualities. Rodent models used in previous literature usually only involve acute exposure, and/or are… Click to show full abstract
BACKGROUND Neuropathic pain patients have described experiencing unprovoked, intermittent pain attacks with shooting, stabbing, and burning qualities. Rodent models used in previous literature usually only involve acute exposure, and/or are unable to manipulate the stimulation intensity in vivo by the experimenter during an experiment. NEW METHOD This paper describes a method to induce controllable pain behaviors in rodents using a wireless portable electronic device that can be manipulated within the course of an experiment. A stimulating electrode was implanted at the L5 spinal nerve location in Sprague-Dawley rats and our custom-built wireless stimulating device was attached to deliver variable stimulation in freely moving animals (50 Hz, 0.5 V; 100 Hz, 1 V). RESULTS Implantation itself did not induce hypersensitivity as measured by the mechanical paw withdrawal threshold test. Observation of pain behaviors (paw elevation and licking) indicated that high stimulation intensity yielded a significant increase in pain behaviors. Even further, high intensity stimulation resulted in a behavioral "wind-up" of pain behaviors that persisted into the resting period when no stimulation was applied. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS This method can be used to study pain behaviors in a controllable way in freely moving rodents in comparison to existing models that are acute and/or are unable to manipulate the stimulation intensity in vivo.
               
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