Shortened pain response time following repeated algesiometric tests in rats

Administration of the hot-plate test once every week for 5 to 8 weeks resulted in a progressive shortening of pain response time in spontaneously hypertensive, normotensive Wistar-Kyoto and Charles River rats. Furthermore, this gradual change in nociceptive response did not appear to be affected by the strain, degree of maturity, or blood pressure status of the animals. It is speculated that re-exposure of the rats to the same algesiometric test may result in "learning," habituation or anticipatory escape behavior.