Rod photoreceptor maturation does not vary with retinal eccentricity in mammalian retina.
OBJECTIVE
Test the hypothesis that the development of mammalian rod outer segments (ROS) varies with retinal eccentricity.


METHODS
During the period of photoreceptor cell development, ROS lengths, opsin mRNA and (rhod)opsin were measured in central and peripheral retina of cows and pigmented rats. Published ROS length and/or rhodopsin data from albino rats, cows and monkeys were re-analyzed. Logistic growth curves were fitted to the newly obtained and published data. Within a species, growth in central and peripheral regions was compared.


RESULTS
The logistic growth curves fit all the data well and provide an excellent view of the developmental increases in ROS length, opsin mRNA and (rhod)opsin in each retinal region. Within a species, the growth curves for ROS length, opsin mRNA and (rhod)opsin concentration are superimposable. The age at which ROS length reaches 50% of its adult value is invariant with eccentricity. An exception to this pattern is the simian parafoveal ROS, which appears to have a delayed course of development.


CONCLUSIONS
The hypothesis is disproved. Unlike rod photoreceptor cell genesis, ROS development is invariant with retinal eccentricity. Primate parafoveal ROS appear to have a different pattern of development.
Timmers
A M
AM
Department of Ophthalmology, University of Florida, Gainesville 32610-0284, USA. atimmers@eye1.eye.ufl.edu
Fox
D A
DA
He
L
L
Hansen
R M
RM
Fulton
A B
AB
D000375:Aging / Q000378:metabolism; D000818:Animals; D002417:Cattle; D000882:Haplorhini / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012160:Retina / Q000254:growth & development* / Q000378:metabolism; D012243:Rhodopsin / Q000378:metabolism; D012374:Rod Cell Outer Segment / Q000254:growth & development* / Q000378:metabolism; D017299:Rod Opsins / Q000235:genetics
D012333:RNA, Messenger; D017299:Rod Opsins; D012243:Rhodopsin