Evidence that the neurotrophic actions of alpha-MSH may derive from its ability to mimick the actions of a peptide formed in degenerating nerve stumps.
The ability of alpha-MSH to facilitate the recovery of sensorimotor nerve function following crush lesion is restricted to a critical period following such a lesion. This period coincided with the initiation of sprouting and the disappearance of the 150 kD neurofilament protein from the degenerating distal stump of the nerve. Degenerating nerve contains a factor that is active in a bioassay system for MSH. This factor could not be detected in control nerves. The hypothesis is forwarded that a neurotrophic factor known to be present in degenerating nerve stumps is an alpha-MSH-like peptide formed by the breakdown of the 150 kD neurofilament protein.
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007381:Intermediate Filament Proteins / Q000502:physiology; D009074:Melanocyte-Stimulating Hormones / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology; D009410:Nerve Degeneration; D009414:Nerve Growth Factors; D009416:Nerve Regeneration; D009419:Nerve Tissue Proteins / Q000502:physiology*; D016900:Neurofilament Proteins; D010455:Peptides / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000502:physiology; D012677:Sensation / Q000502:physiology
D007381:Intermediate Filament Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D010455:Peptides; D009074:Melanocyte-Stimulating Hormones