Calpain activity promotes the sealing of severed giant axons.
A barrier (seal) must form at the cut ends of a severed axon if a neuron is to survive and eventually regenerate. Following severance of crayfish medial giant axons in physiological saline, vesicles accumulate at the cut end and form a barrier (seal) to ion and dye diffusion. In contrast, squid giant axons do not seal, even though injury-induced vesicles form after axonal transection and accumulate at cut axonal ends. Neither axon seals in Ca2+-free salines. The addition of calpain to the bath saline induces the sealing of squid giant axons, whereas the addition of inhibitors of calpain activity inhibits the sealing of crayfish medial giant axons. These complementary effects involving calpain in two different axons suggest that endogenous calpain activity promotes plasmalemmal repair by vesicles or other membranes which form a plug or a continuous membrane barrier to seal cut axonal ends.
Godell
C M
CM
Department of Physiology and Biophysics, University of Texas, Medical Branch, 301 University Boulevard, Galveston, TX 77555-0641, USA.
Smyers
M E
ME
Eddleman
C S
CS
Ballinger
M L
ML
Fishman
H M
HM
Bittner
G D
GD
D000818:Animals; D003400:Astacoidea; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D002154:Calpain / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D049832:Decapodiformes; D004553:Electric Conductivity; D008561:Membrane Fusion / Q000187:drug effects*; D008564:Membrane Potentials; D013045:Species Specificity
D015853:Cysteine Proteinase Inhibitors; D002154:Calpain