Fig. 9. Effects of (A) 0.1 mmol l^–1 and (B) 1.0 mmol l^–1 cimetidine on secreted fluid [TEA] for whole Malpighian tubules. Tubules were bathed in saline alone for the first 20 min. Either 0.1 mmol l^–1 TEA (open symbols) or cimetidine (filled symbols) was added at 20 min. At 60 min either cimetidine (open symbols) or 0.1 mmol l^–1 TEA (filled symbols) was added.