The levels of second messengers such as Ca+2, cAMP and cGMP may regulate the response of the growth cone to a particular cue. Netrin-1 as a guidance molecule depends on intracellular Ca+2 concentration, coactivation of PI3K and PLCgamma, and the type of response depends on the levels of cAMP.
Netrin first stimulates its receptor DCC, resulting in the activation of the enzyme phospholipase C. This then produces the messenger molecules, inositol-1,4,5-trisphosphate (IP3) and DAG, which in turn causes the release of Ca+2 from intracellular stores. Ca+2 release from the stores then activates TRPC channels on the cell surface. DAG activates TRPC3 and TRPC6 in a direct, membrane delimited manner, and IP3 may activate TRPC channels by depleting the ER Ca+2 levels.