Physiological Reviews, Vol 66, 1091-1120, Copyright © 1986 by American Physiological Society
Stress-induced analgesia: adaptive pain suppression
Z. Amit and Z. H. Galina
In this paper we have examined the phenomenon of stress-induced analgesia.
We have described the procedures used to measure analgesia and have
suggested that the tests can be designed not only to indicate changes in
pain threshold but also to allow for the determination of the capacity to
execute adaptive behavior. Aside from enabling the analysis of responses,
tests that induce reflexive as well as nonreflexive behavior may have the
capacity to separate the more complex aspects of pain such as the possible
presence of two components of pain, sensory/discriminative and
motivational/affective. These components may be of fundamental importance
for any attempt to understand the biological significance of SIA. Our
examination of the neurotransmitter and neuropeptide systems has revealed
that they are affected by the same manipulations that induce SIA. These
amines and perhaps peptides play an integral role in learning, motivation,
and performance. We conclude that the functional advantage of a reduction
of pain during stressful situations is significant because it allows the
animal to react in threatening and perhaps critical situations as if there
were no pain. Once the pain system is inhibited, other systems modulate and
mediate adaptive responses that expedite the survival of the animal.
