Visceral nociceptors: a new world order?

There has been a long-standing controversy as to whether or not internal organs are innervated by a special category of 'visceral nociceptor'. Recent experimental studies on the afferent supply of some viscera have thrown new light on this issue by demonstrating the presence of several categories of visceral sensory receptor, including high-threshold receptors, 'silent' nociceptors and intensity-encoding receptors. Advances in the understanding of how the CNS processes nociceptive signals have also helped to clarify the issue. The authors of this report, originally having different points of view, present here a common and closer approach to the visceral nociceptor controversy.