Tu1871 Excretion of Breath Hydrogen Is Reduced by Inhibition of Sulfate Reduction by Molybdate in Rats

Abstract

G A A b st ra ct s increased in the DRG during colitis contains CREB binding sequence in its promoter thus is responsive to CREB activity. AIMS: 1) To examine the phosphorylation of CREB and expression of CGRP by BDNF in vivo and in vitro; and 2) To examine whether the PLC/ calcium pathway is involved in BDNF-induced CREB phosphorylation.METHODS: Colonic inflammation was induced in rats by intracolonic instillation of trinitrobenzene sulfonic acid (TNBS: 1.5 mL/kg of 60 mg/mL solution in 50% EtOH). Control animals received 50% EtOH. Rats were killed on day 3 or 7 following the induction of colitis. CREB phosphorylation was examined by western blot and immunohistochemistry with a specific antibody recognizing CREB phospho-serine 133. The pair-matched DRG explants culture were incubated with BDNF (10 ng/mL) for various time points to examine the effects of BDNF signaling on CREB phosphorylation. Endogenous BDNF was blocked by BDNF neutralizing antibody (36 μg/ kg, i.v.). CGRP expression was examined by real-time PCR. RESULTS: Colitis increased CREB phosphorylation level in the L1 DRG at 3 days and 7 days post TNBS treatment examined by both western blot and immunohistochemistry. CREB phosphorylation in the DRG was expressed in small-to-medium sized sensory neurons. Anti-BDNF treatment of the colitic animals reduced colitis-induced CREB phosphorylation in the L1 DRG. Incubation of DRG explants with BDNF also increased CREB phosphorylation level which was blocked by inhibition of the phospholipase C (PLC) pathway with U-73122. Blockade of endogenous BDNF with BDNF neutralizing antibody also reversed colitis-induced up-regulation of CGRP transcripts in the L1 DRG. CONCLUSION: BDNF regulates CREB activity and CGRP expression through the PLC/calcium pathway in the DRG during colitis. The BDNF-PLC/ calcium-CREB-CGRP axis is an important component in visceral hypersensitivity during colitis.