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Updated: May 19, 2026
Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction
Published on: May 12, 2016
Response properties of slow PIII in the Large (vls) mutant
Neal S Peachey1,2,3, Gwen M Sturgill-Short4
1Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA. neal.peachey@va.gov
Purpose:
Mouse mutants for proteins expressed in the dystrophin-glycoprotein complex at the photoreceptor terminal have electroretinogram (ERG) b-waves with a delayed onset and time course. The b-wave is defined by the sum of PII generated by depolarizing bipolar cells and slow PIII generated by Müller glial cells. In this study, we evaluated the hypothesis that the abnormalities observed in one of these mutants, Large (vls) , are caused by abnormal response properties of slow PIII.
Methods:
To isolate slow PIII, we crossed the Large (vls) mutant to a mouse line (Gpr179 (nob5) ) that lacks the ERG b-wave but maintains normal photoreceptor function and in which retinal degeneration does not occur. ERGs were recorded to strobe flash stimuli after overnight dark adaptation.
Results:
In comparison with control responses, the a-wave and slow PIII had comparable waveforms but were reduced in amplitude in Large (vls) mice. The magnitude of this reduction was comparable for these components, and across stimulus luminance. There was no stimulus condition where the amplitude of slow PIII was larger than control.
Conclusions:
The data obtained are inconsistent with the idea that the b-wave abnormalities noted in Large (vls) mutant mice are caused by abnormal response properties of slow PIII.
