Effect of substance P and somatostatin on migration of polymorphonuclear (PMN) cells in vitro.

The effects of the two neuropeptides, substance P (SP) and somatostatin (SOM), on the migration of polymorphonuclear cells derived from 13 volunteers were investigated. The neuropeptides were applied in concentrations between 10(-12) and 10(-6) M. Only at a concentration of 10(-6) M SP did the chemotaxis of PMN cells increase slightly but statistically significantly. In contrast to SP, SOM showed a significant dose-dependent stimulation of chemotaxis, which was first traceable at 10(-10) M and increased up to 10(-6) M. Although it is uncertain whether in vivo SP and SOM contribute directly to the invasion of PMN cells into the joint cavity, the influence of these neuropeptides on PMN migration in vitro is a further indication of the neuropeptide involvement in the genesis of inflammation.