Flies in which the retina is homozygous for Vha100-13 (made using the 'ey-flp' system described in FBrf0125463) consistently fail to walk toward light in a phototaxis assay. Electro-retinograms from these animals display normal depolarization in response to light stimuli, but exhibit a complete loss of 'on' and 'off' transients, indicative of a failure to evoke a postsynaptic response.
The frequency and amplitude of mini excitatory postsynaptic currents at the neuromuscular junctions of Vha100-12/Vha100-13 embryos is normal. However, excitatory postsynaptic currents induced by stimulation of the motor nerve supplying muscle 6 in these embryos have significantly lower amplitudes than in wild-type. As in wild-type, postsynaptic currents are induced in response to application of a hypertonic solution at the neuromuscular junction.