Activity-dependent regulation of N-cadherin in DRG neurons: differential regulation of N-cadherin, NCAM, and L1 by distinct patterns of action potentials. 
Cell adhesion molecule (CAM) expression is highly regulated during nervous system development to control cell migration, neurite outgrowth, fasciculation, and synaptogenesis.  Using electrical stimulation of mouse dorsal root ganglion (DRG) neurons in cell culture, this work shows that N-cadherin expression is regulated by neuronal firing, and that expression of different CAMs is regulated by distinct patterns of neural impulses.  N-cadherin was down-regulated by 0.1 or 1 Hz stimulation, but NCAM mRNA and protein levels were not altered by stimulation.  L1 was down-regulated by 0.1 Hz stimulation, but not by 0.3 Hz, 1 Hz, or pulsed stimulation.  N-cadherin expression was lowered with faster kinetics than L1 (1 vs. 5 days), and L1 mRNA returned to higher levels after terminating the stimulus.  The RSLE splice variant of L1 was not regulated by action potential stimulation, and activity-dependent influences on L1 expression were blocked by target-derived influences.  The results are consistent with changes in firing pattern accompanying DRG development and suggest that functional activity can influence distinct developmental processes by regulating the relative abundance of different CAMs.