An eyecup preparation for the rat and mouse

The eyecup preparation has traditionally been used to study retinal physiol ogy in lower vertebrates and in some mammals. The procedures for preparing eyecups of the rat and mouse have not been described, however. We now descr ibe methods for preparing and maintaining viable eyecups for these two spec ies. Eyecups were everted over a plastic dome and held in place between the two halves of a superfusion chamber. Fluid exchange in the chamber was rap id, with near total exchange occurring in 9 s. Eyecup viability was tested by monitoring light-evoked retinal responses as the preparation aged. In bo th rat and mouse, the amplitude of the electroretinogram (ERG) b-wave decre ased slowly, declining to 1/2 maximal amplitude in approximate to 70 min. L ight-evoked spike activity of neurons in the ganglion cell layer remained s table for approximate to 3 h and attenuated responses were recorded for an additional 1-2 h. Eyecups were able to dark adapt. Retinal sensitivity, tes ted by monitoring b-wave amplitude, recovered following exposure to an adap ting light. (C) 1999 Elsevier Science B.V. All rights reserved.