Is actin polymerization relevant to neurosecretion? A study on neuroblastoma cells.

We have investigated the relevance of actin rearrangement to neurotransmitter release, in neuroblastoma cell line SH-SY5Y stimulated with carbachol (1 mM). Carbachol reversibly polymerizes actin and releases norepinephrine in undifferentiated SH-SY5Y cells as well as in tetradecanoylphorbol 13-acetate (16 nM) and retinoic acid (5 microM) differentiated SH-SY5Y cells. Microscopic analysis of F-actin distribution indicates polymerization of cortical actin. Prior treatment with iota toxin E from Clostridium perfringens inhibits both carbachol-induced actin polymerization and norepinephrine release, slightly affecting the basal actin network. These data suggest that actin polymerization is associated with norepinephrine release.