Figure 15.

Effect of VU625 (10 µM) on Malpighian tubules isolated from the yellow fever mosquito. (A). Effects on the transepithelial secretion of fluid, Na⁺, K⁺, and Cl⁻ in tubules bathed in 34 mM K⁺ Ringer solution 120 min after the addition of VU625 (period 5, P5, Fig. 10) Experiments were performed in sister tubules isolated from the same mosquito (see Fig. 9). (B). Effects on the basolateral membrane voltage (V_bl) and cell input conductance (g_in). The representative tubule was bathed in Ringer solution containing 3.4 mM or 34 mM K⁺, plus or minus VU625 or barium (Ba²⁺). Probenecid was added to the peritubular bath to block the tubular secretion of VU625. Downward and upward arrows indicate respectively the entry and exit of the voltage-sensing microelectrode into a principal cell of the tubule. * indicates statistical significance. Adapted from Piermarini et al.¹⁵