Expression of Btau\PDE5A^Scer\UAS.cBa in Gyc-89Da neurons under the control of Scer\GAL4^Gyc-89Da.1.9 does not affect sucrose preference. However, caffeine avoidance is eliminated. Conversely, expression of Btau\PDE5A^Scer\UAS.cBa in Gyc-89Db neurons under the control of Scer\GAL4^Gyc-89Db.3.4 eliminates the attraction to sucrose while avoidance to caffeine is unaffected. The loss of sucrose attraction at 21% O[[2]] (atmospheric O[[2]] levels) when Btau\PDE5A^Scer\UAS.cBa is expressed in Scer\GAL4^Gyc-89Db.3.4 neurons is restored by decreasing O[[2]] concentrations to 10%, whereas it has no effect on the loss of avoidance of caffeine when Btau\PDE5A^Scer\UAS.cBa is expressed in Scer\GAL4^Gyc-89Da.1.9 neurons.

Expression of Btau\PDE5A^Scer\UAS.cBa in either Gyc-89Da or Gyc-89Db (under the control of either Scer\GAL4^Gyc-89Da.1.9 or Scer\GAL4^Gyc-89Db.3.4) results in a failure to avoid caffeine (as in wild-type) at low caffeine concentrations (1mM in 1% agar).

Third instar larvae expressing Btau\PDE5A^Scer\UAS.cBa under the control of either Scer\GAL4^Gyc-89Da.1.9 or Scer\GAL4^Gyc-89Db.3.4 show a defect in the normal hypoxia escape response; mutant larvae which have been allowed to burrow into the food and commence feeding take significantly longer than control larvae to leave the food when exposed to low oxygen concentrations.

Basal rates of fluid secretion are reduced in isolated Malpighian tubules expressing Btau\PDE5A^Scer\UAS.cBa under the control of Scer\GAL4^c42. Stimulated fluid secretion by either exogenous cGMP or capa peptide is reduced in Malpighian tubules expressing Btau\PDE5A^Scer\UAS.cBa under the control of Scer\GAL4^c42. Malpighian tubules expressing Btau\PDE5A^Scer\UAS.cBa under the control of Scer\GAL4^c42 do respond in a manner similar to control tubules to application of Dh peptide, despite the lower basal transport levels.