Lansoprazole Raises Somatostatin, Calcitonin Gene-Related Peptide, and Substance P Levels in Healthy Human Plasma

Abstract

levels were measured using a sensitive enzyme immunoassay. Compared with the response of the placebo treated group, lansoprazole caused significant (p < 0.05) increases in somatostatin-, VIP-, substance P- and CGRP-like immunoreactive substance (IS) levels at 120, 120, 90‐240, and 120 min, respectively. Furthermore, lansoprazole significantly suppressed temporary elevation (30 min) of placebo gastrin-IS levels. But lansoprazole had no effect on plasma motilin-IS levels compared with the placebo. In this study, lansoprazole raised somatostatin-IS levels and inhibited the increase in gastrin-IS levels. On the other hand, lansoprazole raised substance P- and CGRP-IS levels. Recently, capsaicin-sensitive afferent nerves have been shown to play an important role in gastric mucosal defensive mechanisms. Capsaicin stimulates afferent nerves and enhances the release of CGRP and substance P in the stomach. We hypothesize that lansoprazole might not only potently inhibit gastric acid secretion but also exert gastroprotective actions via capsaicin-sensitive afferent nerves.