Facilitation of the tail-flick reflex by noxious cutaneous stimulation in the rat: antagonism by a substance P analogue

Effects of noxious cutaneous stimulation on the tail flick reflex were examined in the anaesthetized rat. Noxious stimulation was applied by immersing the distal 4 cm of the tail in water at 55 degrees C for 1.5 min. The tail flick reflex was tested at 3 min intervals by applying a noxious radiant heat stimulus to a region of the tail 10 cm proximal to the tip. Tail immersion reduced reaction time to tail flick by 30% and 20% at 0.5 and 3.5 min …