Acetylcholine as a regulator of neurite outgrowth and motility in cultured embryonic mouse spinal cord

TIME-LAPSE photography was used to examine the effects of acetylcholine on the outgrowth and motility of neurites in cultures of mouse spinal cord. Addition of acetylcholine to the culture medium at concentrations of 100, 10 and 1 mu M, caused inhibition of neurite outgrowth. Outgrowth rates were significantly different from those of controls at all concentrations tested. The motility of the growth cones was significantly reduced by treatment with 100 and 10 mu M acetylcholine. Blockade of the muscarinic receptor by atropine did not significantly alter the effects of acetylcholine on outgrowth or motility. However when the nicotinic antagonist mecamylamine was added at the same time as acetylcholine the inhibitory effects of the acetylcholine were blocked and no changes in the rate of neurite outgrowth or in growth cone motility were detected. These results suggest that acetylcholine may have a role in the regulation of process outgrowth within the spinal cord with these effects mediated through the nicotinic receptor.