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Isolated chick sclera shows a circadian rhythm in proteoglycan synthesis perhaps associated with the rhythm in ocular elongation
- Source :
- Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology. 185:81-90
- Publication Year :
- 1999
- Publisher :
- Springer Science and Business Media LLC, 1999.
-
Abstract
- In the growing chick, ocular elongation is rhythmic, increasing during the day and decreasing at night. Because experimentally induced changes in the rate of ocular elongation are associated with changes in the rate of synthesis of scleral proteoglycans, we asked whether there is a diurnal rhythm in scleral proteoglycan synthesis, whether the rhythm is endogenous, and whether scleras from normal eyes differed from those of faster growing form-deprived eyes. To assess proteoglycan synthesis, we measured the incorporation of labeled sulfate into glycosaminoglycans using two paradigms: (1) punches of sclera were cultured for either 2 or 10 h at various times of day, and (2) punches were cultured in a perifusion system for up to 80 h, and samples of the medium were collected for analysis at 2-h intervals. Synthesis of scleral proteoglycans is higher during the day than during the night. This rhythm persists for at least three cycles in vitro with a period of approximately 24 h. There are no significant differences between rhythms in scleras from normal and form-deprived eyes. Finally, biochemical analyses show the labeled molecule to be similar to aggrecan, the cartilage proteoglycan. We conclude that the synthesis of proteoglycans by scleral chondrocytes is circadian, and we speculate that this rhythm may influence the rhythm in ocular elongation.
- Subjects :
- medicine.medical_specialty
genetic structures
Physiology
Period (gene)
Biology
Eye
Sulfur Radioisotopes
Glycosaminoglycan
Behavioral Neuroscience
Organ Culture Techniques
Rhythm
Vision, Monocular
Internal medicine
medicine
Animals
Circadian rhythm
Ecology, Evolution, Behavior and Systematics
Aggrecan
Cartilage
eye diseases
Circadian Rhythm
Sclera
carbohydrates (lipids)
medicine.anatomical_structure
Endocrinology
Proteoglycan
biology.protein
Proteoglycans
Animal Science and Zoology
sense organs
Chickens
Subjects
Details
- ISSN :
- 14321351 and 03407594
- Volume :
- 185
- Database :
- OpenAIRE
- Journal :
- Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology
- Accession number :
- edsair.doi.dedup.....648811bf3d25fa932ad88c1c643aa394