Techniques for Assessing the Effects of Drugs on Nociceptive Responses

Animal pain tests have been developed primarily for the screening of potential analgesic drugs. In this context, the most important characteristic of a test is that it correctly identify compounds that are analgesic in pathological pain in humans and correctly eliminate compounds without this activity (Taber, 1974 206 ; Frazer and Harris, 1967 92 ; Jacob, 1966 128 ). By this standard, the tail-flick test of D’Amour and Smith (1941) 56 is very accurate in detecting morphine-like drugs, though it is less successful with nalorphine-like drugs and very insensitive to aspirin-like drugs. Other tests have different profiles of sensitivity, and although there seems to be no ideal single laboratory test procedure for the evaluation of analgesics, a combination of several tests has considerable power to identify analgesics (Wood, 1984 237 ).