Figure 3. Examples of effects of TTX (1 μm) and ODQ (10 μm) on contractions induced by SNP (300 μm) of different longitudinal smooth muscle preparations.

A, standard preparation. B, intact preparation. C, longitudinal smooth muscle (LSM) preparation with attached circular muscle (CSM) only. D, isolated longitudinal preparation. a, control contraction produced by SNP. b–d, TTX abolished nerve stimulation (NS)-induced contraction (20 Hz, 0.1 ms pulse duration, 60 V, 5 s), but failed to affect the contraction produced by SNP. e and f, ODQ significantly inhibited the SNP-induced contraction. However, in the presence of ODQ, nerve stimulation still evoked a contraction which was comparable to that without ODQ, implying that this inhibition was not due to the direct inhibition of ODQ on the longitudinal smooth muscle. g, 8-bromo-cGMP (1 mm) mimicked the SNP-induced contraction.