Behavioral characterization of nociceptive sensitization in an animal model of neuropathic chronic pain

CONSTANZA ILARRAZ; MARIA JESUS TRUJILLO; FERNANDO KASANETZ

Workshop; Workshop IFIBIO; 2019

Chronic pain is a debilitating neurological condition of high clinical relevance and the treatments currently available show limited efficacy. The transition to chronic pain remodels neuronal circuits in the brain regions that mediate pain perception. Although initially those changes were believed to reflect peripheral and spinal cord sensitization, brain imaging reports in patients and preclinical studies in animal models suggest that brain neuronal plasticity may actively contribute to the development and persistence of chronic pain.Pain is a complex subjective experience which includes sensory, affective and emotional components mediated by distributed brain networks. Maladaptive changes in all those systems may participate in the chronification of pain. However, the behavioral manifestation of pain was traditionally evaluated by means of reflexive responses, which prevents a proper understanding of the broad mechanisms involved in pain perception.The objective of this work was to set a behavioral paradigm which will enable to differentiate reflex from affective responses toward a diverse variety of stimuli (e.g., noxious vs. neutral) in an animal model of chronic neuropathic pain. For that, we assessed in detail mice behavioral repertoires after stimulation of an injured hind paw.Our preliminary results show that injured animals exhibit affective manifestations after noxious stimuli that do not occur in sham animals. We conclude that this experimental design will allow us to investigate the mechanisms that mediate the different aspects of chronic pain.