The bradykinin BK2 receptor mediates angiotensin II receptor type 2 stimulated rat duodenal mucosal alkaline secretion.
BACKGROUND
This study investigates bradykinin and nitric oxide as potential mediators of AT2-receptor-stimulated duodenal mucosal alkaline secretion. Duodenal mucosal alkaline secretion was measured in methohexital- and alpha-chloralose-anaesthetised rats by means of in situ pH-stat titration. Immunohistochemistry and Western blot were used to identify the BK2 receptors.


RESULTS
The AT2 receptor agonist CGP42112A (0.1 microg kg(-1) min(-1)) administered intravenously increased the duodenal mucosal alkaline secretion by approximately 50 %. This increase was sensitive to the selective BK2 receptor blocker HOE140 (100 ng/kg i.v.), but not to luminal administration of the NOS blocker L-NAME (0.3 mM). Mean arterial pressure did not differ between groups during the procedures. Immunohistochemistry showed a distinct staining of the crypt epithelium and a moderate staining of basal cytoplasm in villus enterocytes.


CONCLUSIONS
The results suggest that the AT2-receptor-stimulated alkaline secretion is mediated via BK2 receptors located in the duodenal cryptal mucosal epithelium.
Ewert
Sara
S
Department of Gastrosurgical Research, Sahlgrenska Academy, Goteborg University, Gothenburg, Sweden. sara.ewert@gastro.gu.se
Johansson
Berndt
B
Holm
Mathias
M
Helander
Herbert F
HF
Fandriks
Lars
L
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004386:Duodenum / Q000098:blood supply / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D005215:Fasting / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000098:blood supply / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D007419:Intestinal Secretions / Q000737:chemistry* / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D044139:Receptor, Angiotensin, Type 2 / Q000502:physiology*; D043782:Receptor, Bradykinin B2 / Q000378:metabolism / Q000502:physiology*
D044139:Receptor, Angiotensin, Type 2; D043782:Receptor, Bradykinin B2