Figure 2.
Frequency-dependence of NANC inhibitory responses to vagus nerve stimulation (80 V, 1.0 ms, 10 s trains) and the effect of NOS inhibition with L-NOARG (10 μM) and cleavage of neuropeptides by α-chymotrypsin (α-CT; 2 U/ml). All experiments were conducted on PGF2α-contracted preparations in the presence of indomethacin (3 μM), bretylium (1 μM) and atropine (1 μM). Note that in experiments on vagus nerve-trachealis preparations effects of L-NOARG (a) and L-NOARG+α-chymotrypsin (b) were examined in separate preparations. All points represent the results of six experiments. *Indicates significant inhibition of responses by L-NOARG (P<0.05, paired t-test); †Indicates significant effect of α-chymotrypsin (P<0.05, paired t-test).