The response of dorsal horn neurones of the cat to intra-arterial bradykinin and noxious radiant heat

Abstract

In chloralose-anaesthetized or decerebrate cats intra-arterially administered bradykinin (BKN) and noxious radiant heat were tested on dorsal horn neurones characterized according to their responses to natural stimuli. Of the 28 neurones which were excited only to non-noxious forms of stimuli, BKN affected 4 while noxious radiant heat was ineffective. BKN also affected relatively few of the nociceptor-driven neurones (18 of 60) and most of these were inhibited, while noxious radiant heat excited the majority of these cells (47 of 60). Therefore, under our experimental conditions, noxious radiant heat would appear to be a more effective and specific noxious stimulus than BKN.