A new assay of thermal-based avoidance test in freely moving mice.

UNLABELLED: The hot plate test is a standard way to measure nociceptive response latencies to a noxious thermal stimulus. Here we have modified the classic hot plate by allowing animals to escape to an adjacent chamber after exposure to the heated surface. In this test, the animals escape to the adjacent chamber after exposure to the hot plate set at 50 degrees C. Repeated exposure to the hot plate resulted in a facilitation of escape responses, as measured by a reduced latency to escape from the noxious thermal stimulus. Signs of nociceptive behavior, such as licking or jumping, were not affected in animals that received hot plate training. The reduction of escape latencies after repeated hot plate exposure might be a useful measure for studying the facilitation of escape responses. In addition, the modified hot plate described here might be useful in studying performance and memory deficits related to noxious thermal stimuli. PERSPECTIVE: We modified a hot plate to measure facilitation of escape responses to a noxious thermal stimulus. The measure of escape responses might be useful in the assessment of memory defects, evaluation of drug therapies, and the behavioral characterization of transgenic mice.