New horizons in our understanding of the spinal physiology and pharmacology of pain processing.

Advances in the management of pain are predicated on the development of our understanding of the underlying systems. This report briefly reviews the peripheral and central substrates that define several mechanisms whereby peripheral mechanical, thermal, and chemical stimuli are encoded. Of particular interest is the growing appreciation of the changes in spinal function that occur with peripheral nerve injury and with repetitive small afferent input. These changes may serve to provide insight into a variety of pain states that are refractory to conventional management approaches.