SUBSTANCE-P INCREASES HELICOBACTER-PYLORI-INDUCED LEUKOCYTE CHEMILUMINESCENCE

Objective: To investigate the effect of administering substance P, one of the key neuromediators of the digestive tract, on Helicobacter pyl ori-induced leukocyte chemiluminescence. Design and methods: Freshly i solated leukocytes from healthy blood donors (1 X 10(6) cells/ml) were stimulated by H. pylori (1 x 10(8) bacteria/ml) and the chemiluminesc ence recorded. Substance P was added at various concentrations (3 x 10 (-6), 1 X 10(-6), 1 X 10(-7) and 1 x 10(-8) mol/1). Results: H. pylori -induced chemiluminescence was significantly increased after adding su bstance P at concentrations of 3 x 10(-6) and 1 x 10(-6) mol/l (285.6 +/- 24.4 and 112 +/- 6.3% of the control values; P<0.01 and P<0.05, re spectively), while no effect was observed at lower concentrations. Con clusions: These data are in agreement with the results of previous stu dies showing that substance P modulates leukocyte function. The demons tration of an increase in H. pylori-induced leukocyte oxidative metabo lism after substance P administration introduces the question of the r ole of neuromodulation in the pathogenesis of the tissue damage induce d by H. pylori and could provide a basis for reconciling the two appro aches, infectious and psychosomatic, to the aetiology of peptic ulcer disease.