A critical analysis of the experimental evaluation of nociceptive reactions in animals.

Because of the complexities of the central nervous system compounded with the ambiguities of interpreting the sensation of and reaction to "pain" in animals, available techniques for experimental evaluation of nociception to various types of stimuli are crude. Simple methods are often associated with artifacts that affect both the qualitative and the quantitative outcome of the test. It is therefore mandatory to control every detail of the experimental protocol. Further, the acuity expected from the experimenter to observe the animals during the test cannot be overemphasized. Additionally the test procedure should not inflict excessive suffering to the animals. It is the purpose of this review to highlight some of the "safeguard" measures to be adopted in order to avoid false-positive and false-negative results and erroneous interpretations and conclusions.