Fig. 4. Effect of L-NAME on subcomponents of embryonic rotation. Changes in rotation rate were measured over 5 s intervals. (A) In the presence of APW, two representative embryos displayed low basal rotation rates (0.3-1.2 r.p.m.) that were interrupted by periodic surges of faster rotation. (B) In the presence of 10 mmol l^-1 L-NAME, two representative embryos displayed lower basal rotation rates (0-0.05 r.p.m.) and fewer surges. Arrows indicate the peak rotation rate during each surge in A and B.