Enhancement of neurite outgrowth from central nervous system neurons in primary culture by thrombin inhibitors.

Previous studies have shown that serine protease inhibitors promote neurite outgrowth from neuroblastoma cells, sympathetic neurons and sensory ganglia in culture. In the present study, a neurite promoting activity of thrombin inhibitors such as hirudin, D-Phe,Pro,Arg-CH2Cl, and paraamidinophenylalanine derivatives, was found in rat embryo (E17) septal neurons in primary culture. In contrast, no effect was shown on choline acetyltransferase activity of septal fragments in culture. These results suggest that thrombin inhibitors might interact with a thrombin-like protease involved in the control of neurite outgrowth.