TY - JOUR
T1 - The development of melanopsin-containing retinal ganglion cells in mice with early retinal degeneration
AU - Ruggiero, Linda
AU - Allen, Charles N.
AU - Lane Brown, R.
AU - Robinson, David W.
PY - 2009/1
Y1 - 2009/1
N2 - In mammals, the neuronal pathways by which rod and cone photoreceptors mediate vision have been well documented. The roles that classical photoreceptors play in photoentrainment, however, have been less clear. In mammals, intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin project directly to the suprachiasmatic nucleus of the hypothalamus, the site of the circadian clock, and thereby contribute to non-image-forming responses to light. Classical photoreceptors are not necessary for photoentrainment as loss of rods and cones does not eliminate light entrainment. Conflicting evidence arose, however, when attenuated phase-shifting responses were observed in the retinal-degenerate CBA/J mouse. In this study, we examined the time course of retinal degeneration in CBA/J mice and used these animals to determine if maturation of the outer retina regulates the morphology, number and distribution of ipRGCs. We also examined whether degeneration during the early development of the outer retina can alter the function of the adult circadian system. We report that dendritic stratification and distribution of ipRGCs was unaltered in mice with early retinal degeneration, suggesting that normal development of the outer retina was not necessary for these processes. We found, however, that adult CBA/J mice have greater numbers of ipRGCs than controls, implicating a role for the outer retinal photoreceptors in regulating developmental cell death of ipRGCs.
AB - In mammals, the neuronal pathways by which rod and cone photoreceptors mediate vision have been well documented. The roles that classical photoreceptors play in photoentrainment, however, have been less clear. In mammals, intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin project directly to the suprachiasmatic nucleus of the hypothalamus, the site of the circadian clock, and thereby contribute to non-image-forming responses to light. Classical photoreceptors are not necessary for photoentrainment as loss of rods and cones does not eliminate light entrainment. Conflicting evidence arose, however, when attenuated phase-shifting responses were observed in the retinal-degenerate CBA/J mouse. In this study, we examined the time course of retinal degeneration in CBA/J mice and used these animals to determine if maturation of the outer retina regulates the morphology, number and distribution of ipRGCs. We also examined whether degeneration during the early development of the outer retina can alter the function of the adult circadian system. We report that dendritic stratification and distribution of ipRGCs was unaltered in mice with early retinal degeneration, suggesting that normal development of the outer retina was not necessary for these processes. We found, however, that adult CBA/J mice have greater numbers of ipRGCs than controls, implicating a role for the outer retinal photoreceptors in regulating developmental cell death of ipRGCs.
KW - Circadian rhythms
KW - Dendritic stratification
KW - Photoentrainment
KW - Photoreceptor cells
KW - SCN
UR - http://www.scopus.com/inward/record.url?scp=58449124078&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=58449124078&partnerID=8YFLogxK
U2 - 10.1111/j.1460-9568.2008.06589.x
DO - 10.1111/j.1460-9568.2008.06589.x
M3 - Article
C2 - 19200239
AN - SCOPUS:58449124078
SN - 0953-816X
VL - 29
SP - 359
EP - 367
JO - European Journal of Neuroscience
JF - European Journal of Neuroscience
IS - 2
ER -