Acid sensors in the gut: a taste of things to come.

Physiological pain is mediated by the transduction of nociceptive stimuli via the peripheral terminals of nociceptors to the spinal dorsal horn neurones, before projection to the cerebral cortex. Pathological states of inflammation and nerve injury alter the transduction properties of peripheral nociceptors and spinal dorsal horn neurones via post-translational changes induced within receptors/ion channels by activation of intracellular transduction cascades. This leads to a sensitized system with altered stimulus response characteristics, which manifests as a clinical hypersensitivity state. With the recent advances in molecular biology it has become possible to identify the various receptors and ion channels involved in nociceptive transduction in health and disease. This new insight is likely to lead to a more targeted approach towards treating both visceral and somatic pain.