Botulinum Toxin a Inhibits Acetylcholine Release from Cultured Neurons In vitro

摘要

Clostridium botulinum type toxin A (BoTx) blocks stimulus-induced acetylcholine(ACh) release from presynaptic nerve terminals at peripheral neuromuscular junctions. However, the detailed mechanism of this effect remains elusive. One obstacle in solving this problem is the lack of a suitable in vitro homogenous cholinergic neuronal model system. We studied the clonal pheochromocytoma PC12 cell line to establish such a model. PC12 cells were differentiated in culture by treatment with 50 ng/ml nerve growth factor (NGF) for 4 days to enhance cellular ACh synthesis and release properties. Stimulation of these cells with high K+ (80 mM) in the perfusion medium markedly increased calcium-dependent (3H)ACh release compared to undifferentiated cells. Stimulated (3H)Ach release was totally inhibited by pretreatment of cells with 2 nM BoTx for 2 h. BoTx inhibition of