BACKGROUND: Capsaicin-sensitive neurons contain various peptides including calcitonin gene-related peptide. This study examines (1) whether calcitonin gene-related peptide is involved in capsaicin-induced gastroprotection and (2) whether nitric oxide and prostaglandin are required for calcitonin gene-related peptide to prevent mucosal injury. METHODS: Gastroprotection by capsaicin or calcitonin gene-related peptide against ethanol-induced gross and histological damage was studied after pretreatment with the calcitonin gene-related peptide receptor antagonist, human calcitonin gene-related peptide8-37, anti-calcitonin gene-related peptide antibodies, and NG-nitro-L-arginine. RESULTS: Protection by capsaicin was dose-dependently (50% inhibitory dose, 305 pmol.kg-1.min-1) antagonized by human calcitonin gene-related peptide8-37 and significantly attenuated by anti-calcitonin gene-related peptide antibodies. NG-nitro-L-arginine dose-dependently inhibited the protective effect of calcitonin gene-related peptide (50% inhibitory dose, 0.9 mg/kg), 3 mg/kg completely blocking protection. L-Arginine reversed the effects of NG-nitro-L-arginine. Protection by calcitonin gene-related peptide was neither associated with increased prostaglandin formation nor inhibited by indomethacin. CONCLUSIONS: The results suggest that calcitonin gene-related peptide is an essential mediator of the protection elicited by stimulation of capsaicin-sensitive neurons and that the protective effect of calcitonin gene-related peptide is lost after blockade of the nitric oxide system but not the prostaglandin system.
BACKGROUND:Capsaicin-sensitive neurons contain various peptides including calcitonin gene-related peptide. This study examines (1) whether calcitonin gene-related peptide is involved in capsaicin-induced gastroprotection and (2) whether nitric oxide and prostaglandin are required for calcitonin gene-related peptide to prevent mucosal injury. METHODS: Gastroprotection by capsaicin or calcitonin gene-related peptide against ethanol-induced gross and histological damage was studied after pretreatment with the calcitonin gene-related peptide receptor antagonist, human calcitonin gene-related peptide8-37, anti-calcitonin gene-related peptide antibodies, and NG-nitro-L-arginine. RESULTS: Protection by capsaicin was dose-dependently (50% inhibitory dose, 305 pmol.kg-1.min-1) antagonized by human calcitonin gene-related peptide8-37 and significantly attenuated by anti-calcitonin gene-related peptide antibodies. NG-nitro-L-arginine dose-dependently inhibited the protective effect of calcitonin gene-related peptide (50% inhibitory dose, 0.9 mg/kg), 3 mg/kg completely blocking protection. L-Arginine reversed the effects of NG-nitro-L-arginine. Protection by calcitonin gene-related peptide was neither associated with increased prostaglandin formation nor inhibited by indomethacin. CONCLUSIONS: The results suggest that calcitonin gene-related peptide is an essential mediator of the protection elicited by stimulation of capsaicin-sensitive neurons and that the protective effect of calcitonin gene-related peptide is lost after blockade of the nitric oxide system but not the prostaglandin system.
Authors: K Arai; T Ohno; T Saeki; S Mizuguchi; K Kamata; I Hayashi; K Saigenji; T Murata; S Narumiya; M Majima Journal: Gut Date: 2003-09 Impact factor: 23.059