CENTRAL AND PERIPHERAL ACTIONS OF THE NSAID KETOPROFEN ON SPINAL-CORDNOCICEPTIVE REFLEXES

Ketoprofen is a non-steroidal antiinflammatory drug (NSAID) which prov ides effective analgesia in situations of pain provoked by tissue infl ammation. However, the location of its analgesic effects, (peripheral tissues versus central nervous system), have not been clearly identifi ed and separated. In the present study the effectiveness of ketoprofen was examined in two different types of experiments: (i) Open field be havioural tests in conscious rats, and (ii) spinal cord nociceptive re flexes (single motor units) activated by electrical and thermal stimul ation in chloralose anaesthetised rats. The experiments were performed in rats with carrageenan-induced inflammation of one hindpaw, or of o ne knee joint. The administration of ketoprofen significantly inhibite d the reduction of exploratory movements caused by inflammation in ope n field experiments. Ketoprofen was also effective in depressing refle x activity evoked by electrical and noxious thermal stimulation of the skin, either in inflamed tissue or in normal tissue of monoarthritic animals. It was also effective in the reduction of reflex wind-up; a p henomenon in which the activity of spinal cord neurones increases prog ressively with high frequency electrical stimulation. We therefore con clude that ketoprofen has central as well as peripheral analgesic acti vity. (C) 1997 Published by Elsevier Science Ltd.