Psychiatr Clin North Am. 1983 Sep; 6(3): 473-87.
Endorphins and pain.
Endorphinergic neurons certainly play a role in the brain's processing of painful stimuli. Endorphins act to alter pain appreciation at many levels within the central nervous system including spinal cord, midbrain, thalamus, and cortex. The activity of this pain-suppressing system may play a role in individual differences in the experience of pain. Endorphinergic mechanisms play a major role in analgesia associated with stress and acupuncture, and perhaps mediate placebo-induced analgesia. Chronic pain influences endorphinergic function perhaps depleting endorphinergic neurons of their neurotransmitters. Endorphin function and pain sensibility are prominently affected in affective illness and schizophrenia. It may be that endorphinergic neurons play a fundamental role in selective attention--a kind of sensory filtering of information flow--in somatosensory and other sensory modalities.