Role of bradykinin in gastric vasodilation caused by hypertonic saline and acid back diffusion.
Protective vasodilation in response to tissue injury and acid back diffusion is associated with release of bradykinin in the rat stomach. We hypothesized that bradykinin might be involved in mechanisms behind such vasodilation via influence on mast cells and sensory neurons. Acid back diffusion after mucosal barrier disruption with hypertonic saline evoked degranulation of mast cells in the rat stomach wall. Acid back diffusion was also associated with increased luminal release of histamine and gastric blood flow in normal rats, but not in mast cell-deficient rats. Bradykinin (BK(2)) receptor blockade inhibited degranulation of submucosal mast cells in the stomach and attenuated gastric vasodilation both in response to acid back diffusion and after stimulation of sensory neurons with capsaicin. Gastric vasodilation caused by mucosal injury with hypertonic saline alone was associated with degranulation of mucosal mast cells. These events were unaffected by inhibition of prostaglandin synthesis, whereas bradykinin (BK(2)) receptor blockade was associated with abolished vasodilation and inhibition of mucosal mast cell degranulation. We conclude that bradykinin is involved in gastric vasodilation caused by hypertonic injury alone via influence on mast cells, and by acid back diffusion via influence on both sensory neurons and mast cells.
Rydning
Astrid
A
Department of Surgery, Norwegian University of Science and Technology, University Hospital Trondheim, St. Olavs Hospital, N-7006 Trondheim, Norway. Astrid.Rydning@stolav.no
Bakkelund
Karin
K
Chen
Duan
D
Falkmer
Sture
S
Grønbech
Jon Erik
JE
D000818:Animals; D001011:Aorta / Q000378:metabolism; D001794:Blood Pressure; D001920:Bradykinin / Q000502:physiology*; D004058:Diffusion; D005753:Gastric Mucosa / Q000378:metabolism; D006632:Histamine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043782:Receptor, Bradykinin B2 / Q000378:metabolism; D012039:Regional Blood Flow; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014664:Vasodilation; D014665:Vasodilator Agents
D043782:Receptor, Bradykinin B2; D014665:Vasodilator Agents; D012965:Sodium Chloride; D006632:Histamine; D001920:Bradykinin