Zheng_1996_Perspect.Dev.Neurobiol_4_205

Cultured Xenopus spinal neurons exhibit chemotropic turning toward the source of neurotransmitters acetylcholine and glutamate. Here we review the experimental evidence that transmitter-induced turning of the growth cone is mediated by an influx of Ca2+, that a gradient of intracellular Ca2+ within the growth cone is responsible for the directional growth cone response, and that asymmetric filopodia formation precedes and is essential for the turning response.