Functional stability of retinal ganglion cells after degeneration-induced changes in synaptic input.
Glutamate released from photoreceptors controls the activity and output of parallel pathways in the retina. When photoreceptors die because of degenerative diseases, surviving retinal networks are left without their major source of input, but little is known about how photoreceptor loss affects ongoing synaptic activity and retinal output. Here, we use patch-clamp recording and two-photon microscopy to investigate morphological and physiological properties of identified types of ON and OFF retinal ganglion cells (RGCs) in the adult (36-210 d old) retinal degeneration rd-1/rd-1 mouse. We find that strong rhythmic synaptic input drives ongoing oscillatory spike activity in both ON and OFF RGCs at a fundamental "beating" frequency of approximately 10 Hz. Despite this aberrant activity, ON and OFF cells maintain their characteristic dendritic stratification, intrinsic firing properties, including rebound firing in OFF cells, balance of synaptic excitation and inhibition, and dendritic calcium signaling. Thus, RGCs are inherently stable during degeneration-induced retinal activity.
Margolis
David J
DJ
Department of Physiology and Biophysics and Program in Neurobiology and Behavior, University of Washington, Seattle, Washington 98195, USA.
Newkirk
Gregory
G
Euler
Thomas
T
Detwiler
Peter B
PB
D000818:Animals; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D012162:Retinal Degeneration / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*