Pain.

Advances in our understanding of the activation of peripheral damage-sensing neurons (nociceptors) over the past year have been complemented by electrophysiological and imaging studies of central nervous system pain-related centres. The manipulation of gene expression in a reversible and cell type specific way combined with imaging and electrophysiological studies holds promise for helping us to identify the spatial and molecular substrates of pain perception with increasing precision and gives hope for improved analgesic therapies.     

Pain pathways and transmission.

Pain has been a major concern of humankind since the ancient times, and it remains one of the most important subjects of all health care professionals. Despite the obvious overwhelming clinical importance, the major advances in its diagnosis and therapy have been made only recently. "How do the sensory apparatus of the body and system of signal transmission relate to pain of peripheral origin?" is the topic of discussion. To do this, it is important to understand what constitutes the total pain experience. It consists of: 1) signal transduction at the peripheral receptor site, 2) signal conduction along the peripheral nerve, 3) pain modulation at the level of the spinal cord, 4) pain perception at the supraspinal site, and 5) the associated sensations, emotional reactions, and effective state. The signal transmission related to pain may be modified by various analgesic agents. Specific analgesic agent has a specific site of action which may be at peripheral receptors, at peripheral nerves, at the level of the spinal cord, at supraspinal levels by activating descending inhibitory systems, or at more cephalad levels by reducing the affective component of pain.     

Pain perception in competitive swimmers.

The pain perception of 30 competitive swimmers was studied using experimentally induced ischaemic pain. The pain thresholds and tolerances of this group were compared with those of 30 club swimmers and 26 non-competitive athletes. While pain thresholds showed little difference between the groups, pain tolerances were considerably different. Pain tolerances of the competitive swimmers varied according to the stage of the training season. The relation between ischaemic pain and that experienced during swimming training was studied using a pain questionnaire composed of several systematically structured verbal categories. Both types of pain were classified along similar dimensions, and it was concluded that the experimentally demonstrated pain tolerances could be generalized to the normal pain perception of the subjects. The origins of the enhanced pain tolerances of the competitive swimmers would seem to lie in their systematic exposure to brief periods of intense pain. These data could have relevance for the treatment of chronic pain in certain diseases.