Pharmacology of pain processing systems

Intergration of nociceptive signaling comprises peripheral, spinal, and sup raspinal sites of the nervous system. Various excitatory or inhibitory neur otransmitter and modulator systems participate in pain processing and modul ation. Chronic pain states are associated with functional and structural al terations of nociceptive pathways. The numerous dynamic changes in the phar macologically distinct systems offer novel targets for selective pharmacoth erapy.