HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Bobu, C. Articles by Hicks, D. Search for Related Content PubMed PubMed Citation Articles by Bobu, C. Articles by Hicks, D.

Photoreceptor Organization and Rhythmic Phagocytosis in the Nile Rat Arvicanthis Ansorgei: A Novel Diurnal Rodent Model for the Study of Cone Pathophysiology

¹From the Laboratoire de Neurobiologie des Rythmes, Université Louis Pasteur, Strasbourg, France; ²The Mary D. Allen Laboratory for Vision Research, Doheny Eye Institute, and the ³Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California.

PURPOSE. To characterize rod and cone distribution, organization, and phagocytosis in the diurnal mouse-like rodent Arvicanthis ansorgei.

METHODS. Retinas of adult A. ansorgei were processed for histology, electron microscopy and immunohistochemistry using rod- and mouse cone-specific antibodies. For phagocytosis studies, retinas were sampled every 3 hours under a 12-hour light–dark cycle and processed for double-label immunohistochemistry. The number of phagosomes in the retinal pigmented epithelium were quantified with a morphometric system.

RESULTS. A. ansorgei retinas were composed of 33% cones and 67% rods, approximately 10 times more cones than mice and rats. Cones were arranged in two cell layers at the scleral surface, distributed uniformly across the entire retina. Cone arrestin was distributed throughout the dark-adapted cones, from outer segments to synapses, whereas short- and mid-wavelength cone opsins were restricted to outer segments. Short-wavelength cone density was mapped in wholemounted retinas, in a significantly higher number in the central region. Rhodopsin immunopositive (rod) phagosomes showed a small peak late in the dark phase, then a large burst 1 to 2 hours after light onset, after decreasing to low baseline levels by 12 AM. Mid-wavelength cone opsin immunopositive (cone) phagosomes were 10 times less numerous than rods, and demonstrated a broad peak 1 to 2 hours after light onset.

CONCLUSIONS. The diurnal rodent A. ansorgei possesses a large number of cones, organized in a strict anatomic array. Rod and cone outer segment phagocytosis and shedding can be monitored simultaneously and show similar profiles but different amplitudes. This species may constitute a valuable novel animal model for investigating cone pathophysiology.

This article has been cited by other articles:

				V. Chrysostomou, J. Stone, S. Stowe, N. L. Barnett, and K. Valter The Status of Cones in the Rhodopsin Mutant P23H-3 Retina: Light-Regulated Damage and Repair in Parallel with Rods Invest. Ophthalmol. Vis. Sci., March 1, 2008; 49(3): 1116 - 1125. [Abstract] [Full Text] [PDF]

				S. C. Khani, B. S. Pawlyk, O. V. Bulgakov, E. Kasperek, J. E. Young, M. Adamian, X. Sun, A. J. Smith, R. R. Ali, and T. Li AAV-Mediated Expression Targeting of Rod and Cone Photoreceptors with a Human Rhodopsin Kinase Promoter Invest. Ophthalmol. Vis. Sci., September 1, 2007; 48(9): 3954 - 3961. [Abstract] [Full Text] [PDF]

				R. F. Mullins, M. H. Kuehn, E. A. Faidley, N. A. Syed, and E. M. Stone Differential Macular and Peripheral Expression of Bestrophin in Human Eyes and Its Implication for Best Disease Invest. Ophthalmol. Vis. Sci., July 1, 2007; 48(7): 3372 - 3380. [Abstract] [Full Text] [PDF]