NITROXIDERGIC VASODILATOR NERVE IN THE CANINE NASAL-MUCOSA

The canine nasal mucosa was studied by in vitro bioassay. Non-adrenerg ic, noncholinergic (NANC) vasodilator response to transmural electrica l stimulation was observed in the presence of guanethidine and atropin e. This vasodilator response was abolished by N-G-nitro-L-arginine (L- NA) which is an inhibitor of nitric oxide (NO) formation but not by N- G-nitro-D-arginine. The inhibitory effect of L-NA was partially revers ed by treatment with L-arginine but not with D-arginine. The vasodilat or response was significantly suppressed by tetrodotoxin. The present results indicate that NO may mediate neurogenic vasodilation in the ca nine nasal mucosa.