Figure 5. Functional effects of dInR manipulations of LK neurons in adult male flies.

A Knockdown and overexpression of dInR in LK neurons produce the same phenotypes when flies are exposed to desiccation (dry starvation). Here the constitutively active dInR (dInR-CA) was used. Both manipulations lead to significantly increased resistance to desiccation, suggesting a malfunction in LK release that decreases diuresis in flies (***p<0.001, n = 120 flies for each genotype from 3 crosses; Log-rank (Mantel-Cox) Test). Note that two different dInR-RNAi lines were tested (a and b). B Feeding, as measured in CAFE assay, is decreased both in flies with dInR knockdown and over expression. Cumulative amount of food eaten over four days is displayed. As a control we used flies with LK neurons hyperpolarized with a constitutively active K-channel (Lk>Ork). These flies display strongly reduced feeding over four days, again suggesting that both manipulations of dInR levels produce malfunction of LK signaling; all manipulations (colored bars) produced significant decreases compared to the four controls shown in gray scale (***p<0.001, n = 10 flies for each genotype in 3 replicates, Two-way ANOVA). C To test whether cell body size of ABLK neurons is affected by activity (level of LK signaling) we exposed wild-type flies (w1118) to desiccation (dry starvation) for 18 h or 18 h desiccation followed by access to water (rewatered flies) for 2 h. As a control normally fed flies were used. No difference in cell body size was noted (ns, not significant for any comparison, n = 7–10 flies for each treatment, One-way ANOVA).