TY - JOUR T1 - Evidence for the Interaction between Nitric Oxide and Vasoactive Intestinal Polypeptide in the Mouse Gastric Fundus JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 945 LP - 950 VL - 299 IS - 3 AU - Yusuf Ergün AU - Nuran Öğülener Y1 - 2001/12/01 UR - http://jpet.aspetjournals.org/content/299/3/945.abstract N2 - The involvement of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) in nonadrenergic noncholinergic (NANC) nerve-induced relaxation and the interaction between NO and VIP were investigated in the mouse gastric fundus.Nω-nitro-l-arginine (l-NOARG; 100 μM) completely inhibited the NANC relaxations induced by electrical stimulation (ES) (0.5, 1, 2, 4, and 8 Hz; 25 V; 1 ms; 15-s trains). Hemoglobin (20 μM), hydroxocobalamin (100 μM), and 1H-[1,2,4,]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 μM) diminished ES-induced relaxations, but α-chymotrypsin (10 U/ml) and VIP antiserum (1/200 dilution) had no effect on NANC relaxations. l-NOARG (100 μM) did not have any effect, whereas ODQ (10 μM) attenuated sodium nitroprusside (SNP; 100 nM)-induced relaxations. α-Chymotrypsin (10 U/ml) had no effect on the response to SNP. Furthermore, α-chymotrypsin (10 U/ml) abolished and VIP antiserum (1/200 dilution) diminished VIP (50 nM)-induced relaxations. l-NOARG (100 μM) caused an inhibition of VIP-induced relaxation that was reversed by l-arginine (1 mM) but not by d-arginine (1 mM). Similarly, ODQ (10 μM) inhibited the responses to VIP. 2-Amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (5 μM) had no effect on these relaxations. l-NOARG (100 μM) and ODQ (10 μM) did not affect isoproterenol (10 nM)-induced relaxations. In conclusion, these results provide evidence that NO is involved in NANC nerve-induced relaxation and the participation of VIP (and related neuropeptides) cannot be excluded in causing relaxation of mouse gastric fundus muscle strips. These findings support the idea that VIP directly stimulates the production of NO by increasing NOS activity and thereby activating soluble guanylyl cyclase in smooth muscle. The American Society for Pharmacology and Experimental Therapeutics ER -