RESUMEN
Increased VIP plasma levels cause severe secretory diarrhea. Moreover, VIP is a major regulator of human intestinal motility. We hypothesized that VIP-mediated intestinal motility disturbances contribute to symptoms in elevated plasma VIP. Ten healthy volunteers were intubated twice with an orojejunal multilumen tube for duodenal manometry, jejunal perfusion of electrolyte and marker solution, and aspiration 10 and 40 cm more distally. All subjects randomly received intravenous infusion of saline and 300 pmol/kg x hr VIP for 5 hr. Results showed that VIP but not saline infusion induced netjejunal sodium secretion, watery diarrhea, and cardiovascular effects (P < 0.04). VIP did not alter intestinal motor activity or the mean duration of the interdigestive motility cycle or of phases I and II but nearly halved the duration of phase III (P = 0.0002). We conclude that increased plasma VIP markedly shortens human phase III activity without influencing other motility parameters. Hence, it is unlikely that VIP-mediated small intestinal motor disturbances cause symptoms in VIPOMA. Yet VIP may contribute to terminate phase III motility.