منابع مشابه
Evolution of vertebrate retinal photoreception
Recent findings shed light on the steps underlying the evolution of vertebrate photoreceptors and retina. Vertebrate ciliary photoreceptors are not as wholly distinct from invertebrate rhabdomeric photoreceptors as is sometimes thought. Recent information on the phylogenies of ciliary and rhabdomeric opsins has helped in constructing the likely routes followed during evolution. Clues to the fac...
متن کاملMammalian Inner Retinal Photoreception
It is now a decade since the first published reports that a small proportion of mammalian retinal ganglion cells are directly photoresponsive. These cells have been termed intrinsically photosensitive retinal ganglion cells (ipRGCs) and comprise a small proportion of the total population of retinal ganglion cells. The demonstration that these ganglion cells respond to light even when isolated f...
متن کاملNonvisual photoreception in the chick iris.
The embryonic chicken iris constricts to light ex vivo, but with characteristics atypical of visual phototransduction. The chick iris was most sensitive to short-wavelength light, demonstrating an action spectrum consistent with cryptochrome rather than with opsin pigments. Pupillary responses did not attenuate after saturating light exposure, but showed paradoxical potentiation. Iris photosens...
متن کاملPineal photosensitivity. A comparison with retinal photoreception.
Pineal photoreceptors of poikilothermic vertebrates possess numerous anatomical, physiological and biochemical similarities to retinal photoreceptors, including the rhythmic melatonin biosynthesis, with nocturnal peaks and low day-time levels. This brief outline will survey the photoreceptor properties of the pineal organ of poikilothermic vertebrates, which suggest that the pineal is not only ...
متن کاملNeural Photoreception in a Lamellibranch Mollusc
The pallial nerves of Spisula solidissima each contain a single afferent nerve fiber which responds directly to illumination of the nerve, and apparently mediates the "shadow" response of siphon retraction. These units show constant-frequency spontaneous activity in the dark; illumination abruptly inhibits this discharge, and cessation of the light stimulus then evokes a prolonged burst of impu...
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ژورنال
عنوان ژورنال: British Journal of Ophthalmology
سال: 1979
ISSN: 0007-1161
DOI: 10.1136/bjo.63.2.140-a