This is your neuron on cannabinoids

Endocannabinoids have a generally depressive activity at adult synapses, but one of their receptors, CB1, is also expressed in the embryonic nervous system. On page 481, Williams et al. report a possible function for these CB1 receptors—they may respond to signals produced by FGF receptor activation. Several cell adhesion molecules promote axon outgrowth via activation of the FGF receptor, and the new work is the first demonstration of cross-talk between this and the endocannabinoid system.

The FGF receptor signaling cascade stimulates the hydrolysis of diacylglycerol (DAG), which is followed by calcium influx and axonal growth. Williams et al. focus on how DAG hydrolysis leads to calcium influx. As the first step of DAG hydrolysis produces the CB1 receptor agonist 2-arachidonylglycerol, the authors focused on the endocannabinoid system as a possible link. They found that, in rat neurons, CB1 antagonists inhibit...