ERG rod a-wave in XXXX .

@entity1 @entity24797 @entity8695 @entity45306 @entity39489
We analyzed the change in the ERG rod a-wave waveform during the course of dark adaptation in two @entity1 with @entity39489 . Two Japanese @entity1 showed a homozygous arrestin @entity45306 mutation. Scotopic flash ERGs were recorded after different periods of dark adaptation. ERG rod a-waves were obtained after subtraction of the cone ERG contribution. The rod a-waves were fitted with a model of the rod receptor signal. The parameters, @entity24797 (maximum a-wave amplitude) and S (sensitivity) were calculated. Longer periods in the dark produced larger rod a-wave but only to the first flash presented. The amplitude of the response to subsequent flashes was essentially independent of the period of dark adaptation. @entity24797 increased with advance of dark adaptation. However, S was nearly constant. Our results suggest that the cause of delayed dark adaptation is not to be sought in the activation of phototransduction process or the regeneration of @entity8695 per se but rather in the deactivation process of the phototransduction cascade.
