Visual pigment coexpression in all cones of two rodents, the Siberian hamster, and the pouched mouse.
OBJECTIVE
To decide whether the identical topography of short- and middle-wavelength cone photoreceptors in two species of rodents reflects the presence of both opsins in all cone cells.


METHODS
Double-label immunocytochemistry using antibodies directed against short-wavelength (S)-and middle- to long-wavelength (M/L)-sensitive opsin were used to determine the presence of visual pigments in cones of two species of rodents, the Siberian hamster (Phodopus sungorus) and the pouched mouse (Saccostomus campestris) from South Africa. Topographical distribution was determined from retinal whole-mounts, and the colocalization of visual pigments was examined using confocal laser scanning microscopy. Opsin colocalization was also confirmed in consecutive semithin tangential sections.


RESULTS
The immunocytochemical results demonstrate that in both the Siberian hamster and the pouched mouse all retinal cones contain two visual pigments. No dorsoventral gradient in the differential expression of the two opsins is observed.


CONCLUSIONS
The retina of the Siberian hamster and the pouched mouse is the first example to show a uniform coexpression of M and S cone opsins in all cones, without any topographical gradient in opsin expression. This finding makes these two species good models for the study of molecular control mechanisms in opsin coexpression in rodents, and renders them suitable as sources of dual cones for future investigations on the role and neural connections of this cone type.
Lukáts
Akos
A
Department of Human Morphology and Developmental Biology, Semmelweis University, Budapest, Hungary.
Dkhissi-Benyahya
Ouria
O
Szepessy
Zsuzsanna
Z
Röhlich
Pál
P
Vígh
Béla
B
Bennett
Nigel C
NC
Cooper
Howard M
HM
Szél
Agoston
A
D000818:Animals; D000911:Antibodies, Monoclonal; D006224:Cricetinae; D019084:Fluorescent Antibody Technique, Indirect; D007124:Immunoenzyme Techniques; D051379:Mice; D018613:Microscopy, Confocal; D017111:Phodopus; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism*; D017299:Rod Opsins / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D017299:Rod Opsins