Hyperalgesia induced by low doses of thymulin injections: possible involvement of prostaglandin E2.

Abstract

Thymulin injection into rats (20-150 ng) i.p. caused a significant reduction in both mechanical (paw pressure test) and thermal (hot plate and tail flick tests) nociceptive thresholds. Thymulin injection also doubled IL-1beta level in the liver of these animals. Induced hyperalgesia was reversed completely by alpha-MSH related tripeptide, Lys-D-Pro-Val in low doses, which is known to antagonize IL-1beta and PGE2 induced hyperalgesia, but was only partly reversed by IL-1beta related tripeptide, Lys-D-Pro-Thr at high doses, which is known to antagonize IL-1beta induced hyperalgesia only. We conclude from these results that thymulin causes hyperalgesia and that this effect is at least in part mediated via PGE2 and its effectiveness at low concentration implies a physiological role for this thymic hormone.

• Authors: B Safieh-Garabedian, S A Kanaan, R H Jalakhian, S Poole, S J Jabbur, N E Saadé
• Journal: Journal of neuroimmunology (J Neuroimmunol) Vol. 73 Issue 1-2 Pg. 162-8 (Mar 1997) ISSN: 0165-5728 [Print] Netherlands
• PMID: 9058772 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-1
• Interleukin-1beta
• Peptide Fragments
• interleukin 1beta (193-195)
• MSH (11-13)
• Melanocyte-Stimulating Hormones
• Thymic Factor, Circulating
• Dinoprostone

Topics

• Animals
• Dinoprostone (physiology)
• Dose-Response Relationship, Drug
• Foot
• Hot Temperature
• Hyperalgesia (chemically induced, physiopathology)
• Injections
• Interleukin-1 (metabolism, pharmacology)
• Interleukin-1beta
• Liver (metabolism)
• Male
• Melanocyte-Stimulating Hormones (pharmacology)
• Pain Threshold (drug effects)
• Peptide Fragments (pharmacology)
• Pressure
• Rats
• Rats, Sprague-Dawley
• Tail (physiology)
• Thymic Factor, Circulating (administration & dosage, pharmacology)