NEURITE OUTGROWTH OF SPINAL NEURONS ON TISSUE-SECTIONS OF EMBRYONIC MUSCLE IS LARGELY INTEGRIN-DEPENDENT

Embryonic chick spinal neurons have been cultured over sections of human foetal muscle to determine which cell adhesion molecules present in embryonic muscle are important in promoting neurite outgrowth. Using blocking antibodies against the major cell adhesion molecules, neural cell adhesion molecule (NCAM), N-cadherin and the beta1 subunit of the integrins, neurite outgrowth was significantly blocked only by anti-integrin antibodies. In addition other agents that block neurite outgrowth stimulated by NCAM, N-cadherin and L1, such as the calcium channel antagonists verapamil and omega-conotoxin and pertussis toxin which inactivates G-proteins also had no effect. This suggests that in this culture system integrins are able to promote neurite outgrowth whereas NCAM and N-cadherin are not.