Muscle reinnervation and IGF-I synthesis are affected by exposure to heparin: an effect partially antagonized by anti-growth hormone-releasing hormone.
Sciatic nerve crush was performed in 2-day-old rats, then reinnervation of the extensor digitorum longus muscle, motor neuron survival, and muscle IGF-I production were monitored. In saline-treated rats, the extent of reinnervation was around 50% and the number of EDL reinnervating motor neurons was significantly reduced. In heparin-treated rats the extent of muscle reinnervation, the recovery of nerve-evoked muscle twitch tension, and the number of motor neurons reinnervating the extensor digitorum longus muscle were greatly enhanced compared to saline-treated rats. In addition, treatment with heparin increased markedly insulin-like growth factor-I levels in denervated muscles. The concomitant exposure to anti-growth hormone releasing hormone partially abolished the stimulatory action of heparin on muscle reinnervation and prevented the increase of insulin-like growth factor-I muscle levels.
Madaschi
Laura
L
Pharmacological Laboratories, Dept. of Medicine, Surgery and Dentistry, Polo H. San Paolo, Via A. Di Rudinì 8, 20142 Milano, Milano, Italy.
Di Giulio
Anna Maria
AM
Gorio
Alfredo
A
D000818:Animals; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors*; D006493:Heparin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D009132:Muscles / Q000294:innervation* / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007334:Insulin-Like Growth Factor I; D006493:Heparin; D013007:Growth Hormone-Releasing Hormone