Retinal control of scleral precursor synthesis.
There is a light-dependent diurnal rhythm in scleral precursor synthesis (SPS). In form-deprivation myopia (FDM) there is an increase in SPS. Daily periods of normal vision prevent FDM, but light intensities that maintain the retinal dark-light switch in its dark state do not, implicating melatonin, dopamine, enkephalin, neurotensin and somatostatin in the control of SPS. FDM is also prevented by pirenzepine, a cholinergic muscarinic antagonist To test if these compounds control the rate of SPS, agonists and antagonists were applied directly to the sclera, but the only effects detected were at very high concentrations, making them physiologically insignificant.
Devadas
M
M
Visual Sciences Group, Research School of Biological Sciences, Australian National University, Canberra, Australia. devadas@rsbs.anu.edu.au
Morgan
I
I
D000221:Adaptation, Ocular / Q000502:physiology; D000818:Animals; D002645:Chickens; D003623:Dark Adaptation / Q000502:physiology; D006025:Glycosaminoglycans / Q000378:metabolism; D008027:Light; D018377:Neurotransmitter Agents / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011509:Proteoglycans / Q000096:biosynthesis*; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012590:Sclera / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism
D006025:Glycosaminoglycans; D018377:Neurotransmitter Agents; D011509:Proteoglycans; D013431:Sulfates