Methods to Study Thermonociception in Rodents

The study of thermonociception in conscious animals is based on the assessment of pain-avoiding behavior from noxious heat or cold stimuli. The conventional tests of heat nociception apply suprathreshold heat stimuli and measure the reflex latency of withdrawal reactions. A novel approach of heat sensitivity measurement is the application of slowly increasing heat stimulation to determine the noxious heat threshold which proved to be highly reproducible and sensitive to standard analgesics. The present chapter aims at providing a guide to the most widely used conventional thermonociceptive tests (constant-temperature hot plate, plantar test, tail-flick test), as well as an introduction to the novel methods, the increasing-temperature hot plate and water bath. In a third section, the methods to test noxious cold sensitivity are briefly described.