PAIN AND ANALGESIC MECHANISMS

The Central Nervous System has a complex structural and functional org anization. Among its functional properties we may emphasize sensorial processes, motor control, vegetative regulation, emotions and cognitiv e processes. The integrity of these functions allows organisms to main tain an interaction with enviroment; furthermore, sensorial activity a ssures communication with either internal or external milieu. Pain as a sensorial process is integrated by a sequence of neuronal signs with important bio-electrical and bio-chemical correlates, that advise abo ut the eventual or current body tissue damage. Some of the neuronal ce lls are in charge of the noxious stimuli reception while others transm it this information to specific neuronal structures; certain cells, by the integration of this information, produce a conscious pain sensati on; moreover, there are cells involved in the motor responses and, fin ally, cells that regulate the noxious information including the analge sia, This work points out general and basic relations between the nerv ous activity and the sensorial process specifically related with pain. In this sense we intend the reader to give a brief look at some of th e sensorial system functions, For this purpose, we describe some elect rophysiological data concerned with the diminution of pain responses a nd the alterations in the receptive fields during experimental noxious activation.