Building blocks of pain: the regulation of key molecules in spinal sensoryneurones during development and following peripheral axotomy

The pathways, synapses and molecules involved in pain processing in the new born are not only required to trigger repair and recuperation but are also involved in the process of forming a mature nervous system. Sensory neurons in the dorsal root ganglion and dorsal horn express a phenomenal array of molecules which contribute to their structural and functional characteristi cs and many of these are developmentally regulated both pre- and postnatall y. In order to understand nociceptive signalling and pain in the neonate we need a clear picture of that regulation. This review concentrates on the c hanging expression of selected key molecules, receptors and channels in the embryo, neonate and adult, which both characterise the sensory neuron and contribute to its response to painful stimuli in normal and pathological co nditions. (C) 1999 International Association for the Study of Pain. Publish ed by Elsevier Science B.V.