Receptive field properties of cat retinal ganglion cells during short-term IOP elevation.

PURPOSE

To examine and compare receptive field properties of cat retinal ganglion cells before and during intraocular pressure (IOP) elevation.

METHODS

Responses of cat retinal ganglion cells to two sets of specially designed light or dark spots and annuli were recorded extracellularly. Receptive field properties were studied comparatively before and during short-term constant IOP elevation induced by keeping the retinal perfusion pressure at a critical level of about 30 mm Hg.

RESULTS

All the responses, including properties of different types of receptive fields and different components of the cells' receptive fields, decreased during short-term IOP elevation. The responses of off-center cells were more tolerant of IOP elevation than those of on-center cells, whereas the responses of Y cells were less sensitive to IOP elevation than those of X cells. The responses of the centers of the receptive fields exhibited pronounced resistance to IOP elevation than those of the surround. The peak responses of the post-stimulus time histogram of all cells declined less than the mean responses during IOP elevation.

CONCLUSIONS

The varied effects of short-term IOP elevation on different types (X and Y, on-center and off-center) of retinal ganglion cells and their receptive field properties may reflect the different degrees of ischemic effects on the retinal pathways that project to the different types of ganglion cells.