 |
||||
|
||||
|
||||
|
||||
|
||||
The Journal of Neuroscience, October 27, 2004, 24(43):9693-9697; doi:10.1523/JNEUROSCI.2556-04.2004
Previous Article | Next Article
BRIEF COMMUNICATION
Classical Photoreceptors Regulate Melanopsin mRNA Levels in the Rat Retina
Katsuhiko Sakamoto, Cuimei Liu, andGianluca Tosini Neuroscience Institute and National Science Foundation Center for Behavioral Neuroscience, Morehouse School of Medicine, Atlanta, Georgia 30310-1495
Recent studies have demonstrated that melanopsin is a key photopigment in the mammalian circadian system. This novel opsin is exclusively expressed in retinal ganglion cells that are intrinsically sensitive to light, perhaps responding via a melanopsin-based signaling pathway. Previous investigations using transgenic mice have also demonstrated that ablation of the classical photoreceptors and of melanopsin prevents entrainment of several circadian rhythms, thus demonstrating that these photoreceptors are necessary and sufficient for circadian photoreception. In this study, we investigated the effect of photoreceptor degeneration on melanopsin mRNA regulation in RCS/N-rdy rats (Royal College of Surgeons rats with a defect in the retinal dystrophy gene). We used animals at postnatal day 21 (P21), P33, P45, and P60. At P60 degeneration of the retina in RCS/N-rdy has advanced to the point where the majority of the photoreceptors have degenerated. Our data indicate that melanopsin mRNA levels were rhythmic in light/dark cycle and in constant darkness in congenic controls (RCS/N-rdy+) and in RCS/N-rdy at P21 (i.e., before the degeneration of the photoreceptors). On the other hand, in RCS/N-rdy at P60, melanopsin mRNA levels were greatly reduced (<90%) and not rhythmic. Photoreceptor degeneration did not affect the expression of pituitary adenylate cyclase-activating polypeptide mRNA (a marker for melanopsin-containing ganglion cells). Our results suggest that classical photoreceptors (rods and cones) regulate the expression of melanopsin mRNA in the rat. Because RCS/N-rdy rats are a model for studies on retinitis pigmentosa in human, our data may provide an important insight on melanopsin function in patients affected by retinitis pigmentosa.
Key words: melanopsin; circadian rhythm; RCS rat; circadian photoreception; retina; photoreceptor degeneration
Received June 28, 2004; revised September 3, 2004; accepted September 22, 2004.
This article has been cited by other articles:
S. Thompson, R. F. Mullins, A. R. Philp, E. M. Stone, and N. Mrosovsky
Divergent Phenotypes of Vision and Accessory Visual Function in Mice with Visual Cycle Dysfunction (Rpe65rd12) or Retinal Degeneration (rd/rd)
Invest. Ophthalmol. Vis. Sci., June 1, 2008; 49(6): 2737 - 2742.
[Abstract] [Full Text] [PDF]
A. T. E. Hartwick, J. R. Bramley, J. Yu, K. T. Stevens, C. N. Allen, W. H. Baldridge, P. J. Sollars, and G. E. Pickard
Light-Evoked Calcium Responses of Isolated Melanopsin-Expressing Retinal Ganglion Cells
J. Neurosci., December 5, 2007; 27(49): 13468 - 13480.
[Abstract] [Full Text] [PDF]
E. Drouyer, C. Rieux, R. A. Hut, and H. M. Cooper
Responses of Suprachiasmatic Nucleus Neurons to Light and Dark Adaptation: Relative Contributions of Melanopsin and Rod Cone Inputs
J. Neurosci., September 5, 2007; 27(36): 9623 - 9631.
[Abstract] [Full Text] [PDF]
J. T. Wang, N. J. Kunzevitzky, J. C. Dugas, M. Cameron, B. A. Barres, and J. L. Goldberg
Disease Gene Candidates Revealed by Expression Profiling of Retinal Ganglion Cell Development
J. Neurosci., August 8, 2007; 27(32): 8593 - 8603.
[Abstract] [Full Text] [PDF]
J. Ostergaard, J. Hannibal, and J. Fahrenkrug
Synaptic Contact between Melanopsin-Containing Retinal Ganglion Cells and Rod Bipolar Cells
Invest. Ophthalmol. Vis. Sci., August 1, 2007; 48(8): 3812 - 3820.
[Abstract] [Full Text] [PDF]
R. J. Lucas
Chromophore regeneration: Melanopsin does its own thing
PNAS, July 5, 2006; 103(27): 10153 - 10154.
[Full Text] [PDF]
|
|
|
|
 |
|