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Photic regulation of circadian rhyth...

Provencio, Ignacio.

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Photic regulation of circadian rhythms in retinally degenerate mice.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Photic regulation of circadian rhythms in retinally degenerate mice./
Author:	Provencio, Ignacio.
Description:	194 p.
Notes:	Adviser: Russell G. Foster.
Contained By:	Dissertation Abstracts International57-01B.
Subject:	Biology, Neuroscience. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9616033

Photic regulation of circadian rhythms in retinally degenerate mice.
Provencio, Ignacio.

Photic regulation of circadian rhythms in retinally degenerate mice. - 194 p.

Adviser: Russell G. Foster.

Thesis (Ph.D.)--University of Virginia, 1996.

In conclusion, although rods are not required for "circadian photoreception", cones remain a viable candidates. We cannot, however, exclude the possibility that a non-rod, non-cone photoreceptor class serves this function.Subjects--Topical Terms:

1017680
Biology, Neuroscience.

Photic regulation of circadian rhythms in retinally degenerate mice.
LDR:03273nam 2200301 a 45 001 970736
005 20110921
008 110921s1996 eng d
035 $a (UMI)AAI9616033
035 $a AAI9616033
040 $a UMI $c UMI
100 1 $a Provencio, Ignacio. $3 1294781
245 1 0 $a Photic regulation of circadian rhythms in retinally degenerate mice.
300 $a 194 p.
500 $a Adviser: Russell G. Foster.
500 $a Source: Dissertation Abstracts International, Volume: 57-01, Section: B, page: 0161.
502 $a Thesis (Ph.D.)--University of Virginia, 1996.
520 $a In conclusion, although rods are not required for "circadian photoreception", cones remain a viable candidates. We cannot, however, exclude the possibility that a non-rod, non-cone photoreceptor class serves this function.
520 $a Circadian rhythms in mammals can be regulated by light. The photoreceptors that mediate this regulation are unknown but almost certainly reside within the eye. To characterize these photoreceptors, we have undertaken experiments in a retinally degenerate animal model. The retinal degenerate (rd) mouse suffers a profound degeneration of rod photoreceptors early in postnatal development. Cone photoreceptors also degenerate at a protracted rate, but a subset of these cells, devoid of outer segments, survive into adulthood. The differential effect of this mutation upon the rods and cones makes the rd mouse a good model to study the role of these photoreceptors in the photoentrainment of circadian rhythms.
520 $a Rods are not required for photoentrainment because aged rd mice phase shift circadian locomotor activity rhythms in response to light. Furthermore, the sensitivity of the rd mouse circadian system to light is indistinguishable from wild-type controls. The characteristics of the photoreceptors mediating this regulation of circadian rhythms are very cone-like. Photopigment chromophore cannot be photoisomerized to the extent observed in the rod-dominated wild-type eye. This is characteristic of cone systems. Also, the spectral sensitivities of phase shifting circadian activity rhythms closely matches the sensitivities of the two known cone classes within the mouse retina.
520 $a Using neurotropic viruses, we have attempted to label retrogradely cells within the retina that may be involved in the photic input pathway to the circadian system. We have identified two classes: (1) A morphologically distinct class of retinal ganglion cells that are few in number, widely distributed, and have large sparsely branched dendritic arbors. The distribution suggests the involvement of both known cone classes in the regulation of circadian rhythms and is consistent with the above-mentioned spectral sensitivities. (2) Amacrine-like cells found within the inner margin of the inner nuclear layer. To our knowledge, these cells are the first identification of inner retinal neurons that may be involved in the photic input pathway to the circadian axis.
590 $a School code: 0246.
650 4 $a Biology, Neuroscience. $3 1017680
650 4 $a Health Sciences, Ophthalmology. $3 1019445
690 $a 0317
690 $a 0381
710 2 0 $a University of Virginia. $3 645578
773 0 $t Dissertation Abstracts International $g 57-01B.
790 $a 0246
790 1 0 $a Foster, Russell G., $e advisor
791 $a Ph.D.
792 $a 1996
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9616033