Functional changes in inner retinal neurons in animal models of photoreceptor degeneration

Retinitis Pigmentosa (RP) refers to a heterogeneous group of inherited disorders that result in the death of rod and cone photoreceptors. There is now abundant evidence to suggest that inner retinal neurons, particularly the bipolar and horizontal cells, undergo significant morphological changes and changes in neurotransmitter receptor expression in response to photoreceptor degeneration. Some of these alterations could impact the choice and success of intervention strategies for these conditions, and it is therefore necessary to understand the timing and nature of any functional deficits resulting from degenerative changes. This paper will review the evidence for functional alterations in the inner retina in animal models of (RP), with particular emphasis on the bipolar and ganglion cells.