Circadian dysfunction in P23H rhodopsin transgenic rats: effects of exogenous melatonin

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Title: Circadian dysfunction in P23H rhodopsin transgenic rats: effects of exogenous melatonin
Authors: Lax, Pedro | Baño Otalora, Beatriz | Esquiva Sobrino, Gema | Rol de Lama, María de los Ángeles | Madrid Pérez, Juan Antonio | Cuenca, Nicolás
Research Group/s: Neurobiología del Sistema Visual y Terapia de Enfermedades Neurodegenerativas (NEUROVIS)
Center, Department or Service: Universidad de Alicante. Departamento de Fisiología, Genética y Microbiología
Keywords: Chronodisruption | Core temperature rhythm | Electroretinogram | Melatonin | P23H | Retinitis pigmentosa
Knowledge Area: Oftalmología | Fisiología
Issue Date: 9-Nov-2010
Publisher: John Wiley & Sons
Citation: LAX ZAPATA, Pedro, et al. “Circadian dysfunction in P23H rhodopsin transgenic rats: effects of exogenous melatonin”. Journal of Pineal Research. Vol. 50, Issue 2 (March 2011). ISSN 0742-3098, pp. 183-191
Abstract: This study focuses on the effects of retinal degeneration on the circadian patterns of P23H rats, as well as on the effect of exogenous melatonin administration. To this end, the body temperature of P23H and Sprague–Dawley rats was continuously monitored and their retinas examined at different stages of degeneration, by means of histological labeling and electroretinogram recordings. Melatonin (2 mg/kg BW/day) was supplied ad libitum throughout the experiment to a subset of animals. The body temperature recordings from wild-type and mutant animals showed no differences in the periodogram and the pattern of the mean waveform. However, a progressive decrease in the relative amplitude of the rhythm (RA), a decline in the coupling strength of the rhythm to environmental zeitgebers (interdaily stability, IS) and increased rhythm fragmentation (intradaily variability, IV) were observed in P23H rats, when compared to wild-type animals. The P23H animals showed a progressive decrease in light-induced retinal responses until reaching 18 months of age. By this age, all photoreceptors had already disappeared, and no responses were found in the EGRs. Exogenous administration of melatonin improved the visual response of P23H rats. In fact, the maximum b-wave recorded at 14 months of age was significantly higher in melatonin-treated P23H rats than in the control animals. Furthermore, the maximum b-wave recorded for P23H rats at the age of 14 months significantly correlated with RA, IS, and IV. This leads us to conclude that vision loss in P23H rats is correlated with a progressive fragmentation of their circadian patterns. Both effects are partially reversed by melatonin administration.
Sponsor: This work was supported by MICINN (AP2006-04117, BFU2007-60658/BFI, and BFU2009-07793/BFI), Instituto de Salud Carlos III (RETICS RD07/0062/0012, RETICEF RD06/0013/0019), FUNDALUCE, ONCE, Fundación Médica Mutua Madrileña.
ISSN: 0742-3098 (Print) | 1600-079X (Online)
DOI: 10.1111/j.1600-079X.2010.00827.x
Language: eng
Type: info:eu-repo/semantics/article
Rights: The definitive version is available at
Peer Review: si
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Appears in Collections:INV - NEUROVIS - Artículos de Revistas

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