Publication Date:
2012-07-03
Description:
Peripheral activation of corticotropin-releasing factor receptor type 2 (CRF 2 ) by urocortin 1, 2, or 3 (Ucns) exerts powerful effects on gastric function; however, little is known about their expression and regulation in the stomach. We investigated the expression of Ucns and CRF 2 isoforms by RT-PCR in the gastric corpus (GC) mucosa and submucosa plus muscle (S+M) or laser captured layers in naive rats, their regulations by lipopolysaccharide (LPS, 100 μg/kg ip) over 24 h, and the effect of the CRF 2 antagonist astresssin 2 -B (100 μg/kg sc) on LPS-induced delayed gastric emptying (GE) 2-h postinjection. Transcripts of Ucns and CRF 2b, the most common wild-type CRF 2 isoform in the periphery, were expressed in all layers, including myenteric neurons. LPS increased Ucn mRNA levels significantly in both mucosa and S+M, reaching a maximal response at 6 h postinjection and returning to basal levels at 24 h except for Ucn 1 in S+M. By contrast, CRF 2b mRNA level was significantly decreased in the mucosa and M+S with a nadir at 6 h. In addition, CRF 2a , reportedly only found in the brain, and the novel splice variant CRF 2a-3 were also detected in the GC, antrum, and pylorus. LPS reciprocally regulated these variants with a decrease of CRF 2a and an increase of CRF 2a-3 in the GC 6 h postinjection. Astressin 2 -B exacerbated LPS-delayed GE (42–73%, P 〈 0.001). These data indicate that Ucn and CRF 2 isoforms are widely distributed throughout the rat stomach and inversely regulated by immune stress. The CRF 2 signaling system may act to counteract the early gastric motor alterations to endotoxemia.
Print ISSN:
0193-1857
Electronic ISSN:
1522-1547
Topics:
Medicine
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