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Circadian rhythms in the retina of rats with photoreceptor degeneration
Author(s) -
Sakamoto Katsuhiko,
Liu Cuimei,
Tosini Gianluca
Publication year - 2004
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02571.x
Subject(s) - circadian rhythm , retina , kainic acid , biology , circadian clock , light effects on circadian rhythm , retinal , neuroscience , suprachiasmatic nucleus , melatonin , endocrinology , medicine , microbiology and biotechnology , glutamate receptor , genetics , biochemistry , receptor
Previous studies have demonstrated that the mammalian retina contains a circadian clock system that controls several retinal functions. In mammals the location of the retinal circadian clock is unknown whereas, in non‐mammalian vertebrates, earlier work has demonstrated that photoreceptor cells contain the circadian clock. New experimental evidence has suggested that in mammals the retinal circadian clock may be located outside the photoreceptor cells. In this study we report that circadian rhythms in Aa‐nat mRNA ( in vivo ) and melatonin synthesis ( in vitro ) are still present in the retina of rats lacking photoreceptors. The circadian pacemaker(s) controlling such rhythms is probably located in kainic acid sensitive neurons in the inner retina since kainic acid injections abolished the rhythmicity. These data are the first direct demonstration that circadian rhythmicity in the mammalian retina can be generated independently from the photoreceptors and the suprachiasmatic nuclei of the hypothalamus.