Growth cones, the motile structures at the tips of advancing axons and dendrites, respond to
a wide range of cues by either turning towards or away from the cue. Cytosolic calcium
signals appear to mediate a large fraction of both types of response. Calcium signals can be
generated by influx through plasma membrane channels or by release from intracellular
stores. While neurotransmitters can elicit calcium influx through ionotropic receptors, other
chemical cues open plasma membrane voltage gated calcium channels by a mechanism …