Pain: current aspects on peripheral and central sensitization.

BACKGROUND AND OBJECTIVES Current research has focused on the biochemical and structural plasticity of the nervous system secondary to tissue injury. The mechanisms involved in the transition from acute to chronic pain are complex and involve the interaction of receptor systems and the flow of intracellular ions, second messenger systems, and new synaptic connections. The aim of this article was to discuss the new mechanisms concerning peripheral and central sensitization. CONTENTS Tissue injury increases the response of nociceptors, known as sensitization or facilitation. These phenomena begin after the local release of inflammatory mediators and the activation of the cells of the immune system or specific receptors in the peripheral and central nervous system. CONCLUSIONS Tissue and neuronal lesions result in sensitization of the nociceptors and facilitation of the central and peripheral nervous conduction.