Fig. 6. The effects of the sGC inhibitor, ODQ, and the cGMP analogue, 8-Br-cGMP, on the digging rhythm. (Ai) A 10 min bath application of 0.1 mmol l^–1 ODQ resulted in a significant decrease in cycle frequency (t=2.85, ^*P<0.05, mean ± s.e.m. from five animals). (Aii) An example showing that a 10 min bath application of ODQ resulted in a decrease in the cycle number that was reversed by a 30 min wash with locust saline. (B) The simultaneous bath application of L-arginine and ODQ resulted in no statistically significant difference between control and test values (t=–1.34, P>0.05, mean ± s.e.m. from five animals). (Ci) A 10 min bath application of 0.1 mmol l^–1 8-Br-cGMP resulted in a significant increase in cycle frequency of the digging rhythm (t=2.22, ^*P<0.05, mean ± s.e.m. from six animals). A 30 min wash with locust saline did not result in the cycle frequency returning back to its original value. (Cii) An example showing that bath application of 8-Br-cGMP resulted in an increase in the number of cycles of muscle activity of the digging rhythm, from a control value of four cycles to a test value of five within the same time period.