Anand P, McGregor G P, Gibson S J, Maden M, Polak J M, Bloom S R
Department of Medicine, Hammersmith Hospital, London, U.K.
Neurosci Lett. 1987 Dec 4;82(3):241-5. doi: 10.1016/0304-3940(87)90263-1.
That substance P may be a neurotrophic factor in urodele limb regeneration was investigated in the axolotl (Ambystoma mexicanum). Two weeks after section of the peripheral nerves to the forelimb, there was a marked increase in substance P-like immunoreactivity (IR) content of the nerves proximal to the lesion. A smaller increase occurred as early as 3 days after section of nerves innervating a regrowing limb bud (blastema), and substance P-IR fibres were observed by immunocytochemistry to innervate blastema tissue. As substance P-IR by applying capsaicin to peripheral nerve--capsaicin had no effect on substance P-IR in either intact or injured axolotl nerves. Substance P fulfills a number of criteria of a trophic substance in axolotl limb regrowth.
