Preface to the special issue "Pain".

This preface introduces the Journal of Neurochemistry Special Issue on pain research. While acute pain provides important sensory information, which aids in the protection of an organism, it can in some cases transition into a chronic state. Unfortunately, chronic pain is a highly disabling state characterised by intense and abnormal pain sensations, which are exacerbated by problematic psychosocial disturbances that are poorly treated by current drugs. This issue includes several reviews that address current issues spanning basic to clinical research on a range of pain syndromes. Also included is a collection of basic research articles investigating important aspects of pain signalling through to whole body aspects of pain integration.