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Antiinflammatory activity of a COOH-terminal fragment of the neuropeptide alpha-MSH
1Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235.
Abstract:
The endogenous neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH 1-13), previously found to have marked antipyretic activity, inhibits histamine-induced increases in vasopermeability. The primary antipyretic amino acid message sequence is believed to be the COOH-terminal trieptide, lysine-proline-valine. In recent preliminary research this tripeptide inhibited increases in vasopermeability, raising the possibility that this portion of the alpha-MSH molecule has general antiinflammatory activity. To test this idea, the effects of graded doses of alpha-MSH [11-13] on ear swelling induced by picryl chloride in mice were compared with the effects of saline and a large dose of corticosteroid. Alpha-MSH [11-13] inhibited swelling in a dose-related fashion. This result, together with previous findings, suggests that endogenous circulating alpha-MSH and its COOH-terminal fragments may contribute to modulation of physiological responses in host defense. If this is true, it may be possible to develop new peptide drugs or mimetics based on the tripeptide that are useful in treating inflammation.
Insights
The tripeptide lysine-proline-valine, a fragment of alpha-melanocyte stimulating hormone (alpha-MSH), demonstrates anti-inflammatory effects by reducing swelling. This suggests potential for new peptide-based anti-inflammatory drugs.
Area of Science:
- Immunology
- Endocrinology
- Pharmacology
Background:
- Endogenous neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) exhibits antipyretic and anti-vasopermeability properties.
- The COOH-terminal tripeptide (lysine-proline-valine) of alpha-MSH is implicated in its antipyretic activity and has shown preliminary anti-vasopermeability effects.
- This suggests the tripeptide fragment may possess broader anti-inflammatory capabilities.
Purpose of the Study:
- To investigate the anti-inflammatory potential of the alpha-MSH [11-13] tripeptide.
- To determine if alpha-MSH [11-13] can inhibit inflammatory responses in a mammalian model.
Main Methods:
- The study utilized a mouse model of ear swelling induced by picryl chloride.
- Graded doses of alpha-MSH [11-13] were administered and compared to saline and corticosteroid treatments.
- The effect on ear swelling was quantified to assess anti-inflammatory activity.
Main Results:
- Alpha-melanocyte stimulating hormone [11-13] significantly inhibited ear swelling in a dose-dependent manner.
- The tripeptide's anti-inflammatory effect was comparable to a large dose of corticosteroid in this model.
- These findings support the hypothesis that the tripeptide fragment possesses anti-inflammatory activity.
Conclusions:
- The alpha-MSH [11-13] tripeptide exhibits significant anti-inflammatory effects, reducing swelling in a dose-related manner.
- Endogenous alpha-MSH and its COOH-terminal fragments may play a role in regulating host defense and inflammation.
- The findings suggest the potential development of novel peptide-based therapeutics for inflammatory conditions based on this tripeptide sequence.