Sound stress-induced long-term enhancement of mechanical hyperalgesia in rats is maintained by sympathoadrenal catecholamines.

Abstract

UNLABELLED:

Although stress plays an important role in chronic widespread pain syndromes, such as fibromyalgia, the underlying mechanism has remained elusive. We have recently demonstrated, in a model of chronic widespread pain, that prolonged enhancement of immune mediator hyperalgesia, induced by unpredictable sound stress, requires a contribution of both the sympathoadrenal (epinephrine) and the hypothalamic-pituitary adrenal (corticosterone) neuroendocrine stress axes. Because this stress protocol produced sustained elevation of plasma epinephrine, in the current study we tested the hypothesis that the sympathoadrenal axis also plays a role in maintenance of symptoms in this model of chronic widespread pain. After establishment, adrenal medullectomy abolished the enhancement of epinephrine-induced cutaneous and muscle hyperalgesia. Administration of stress levels of epinephrine to adrenal medullectomized rats reconstituted the pain phenotype. These observations suggest that the sympathoadrenal stress axis plays a major role in the induction as well as maintenance of stress-induced enhancement of mechanical hyperalgesia, mediated by prolonged elevation of circulating epinephrine.

PERSPECTIVE:

We present data showing mechanical hyperalgesia persisting for up to 28 days after exposure to sound stress, with evidence that the sympathoadrenal axis mediator epinephrine plays a major role. These findings could have clinical implications with regard to novel potential treatments for chronic widespread pain syndromes, such as fibromyalgia.

• Authors: Sachia G Khasar, Olayinka A Dina, Paul G Green, Jon D Levine
• Journal: The journal of pain (J Pain) Vol. 10 Issue 10 Pg. 1073-7 (Oct 2009) ISSN: 1528-8447 [Electronic] United States
• PMID: 19576859 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Catecholamines
• Epinephrine

Topics

• Acoustic Stimulation (adverse effects)
• Adrenal Medulla (metabolism)
• Animals
• Catecholamines (blood, metabolism, pharmacology)
• Chronic Disease
• Disease Models, Animal
• Epinephrine (blood, metabolism, pharmacology)
• Hyperalgesia (complications, metabolism, physiopathology)
• Injections, Intramuscular
• Injections, Subcutaneous
• Male
• Neuropsychological Tests
• Nociceptors (drug effects, physiology)
• Pain Threshold (drug effects, physiology)
• Physical Stimulation (adverse effects)
• Rats
• Rats, Sprague-Dawley
• Sound (adverse effects)
• Stress, Psychological (complications, metabolism, physiopathology)
• Sympathetic Nervous System (metabolism)
• Time Factors
• Touch (physiology)