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Effect of endothelin on the gene expression of melanopsins (Opn4x and Opn4m) and endothelin receptor subtype ETc in melanophores of Xenopus laevis

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Author(s):
Maria Nathália de Carvalho Magalhães Moraes
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
Defense date:
Examining board members:
Ana Maria de Lauro Castrucci; Daniel Carneiro Carrettiero; Mauro César Isoldi
Advisor: Ana Maria de Lauro Castrucci
Abstract

The biological clocks are critical for synchronizing the behavior of organisms to changes in photoperiod. All rhythmic changes are crucial to the survival of the species since they provide for internal adjustments to coincide with the phase of the cycle most favorable. Many of these biological rhythms are clearly associated with the light-dark cycle, of major importance for species that have some type of photosensitive pigment. Melanophores of Xenopus laevis are photosensitive, responding to light with dispersion of melanin granules, due to the presence of two melanopsins, Opn4x and Opn4m. The pigment cells of ectothermic vertebrates respond with pigment migration to a variety of agents including the endothelins. In teleost fish, ETs induce pigment aggregation in melanophores, whereas in amphibians, ET-3 induces the dispersion of pigment granules in melanophores of Xenopus laevis and Rana catesbeiana, by activation of ETc. We proposed to determine the temporal pattern of gene expression of the ETc receptor and melanopsins in dermal melanophores of X. laevis in culture as well as the effects of endothelin-3 on the temporal expression of the 3 genes. Using quantitative PCR, we demonstrated that 12L: 12D regimen, combined with medium changes, as well as the treatment with 10-9 and 10-8M endothelin-3, was able to synchronize the expression of Opn4x and Opn4m. However, ETc receptor seems not to be synchronized by light-dark cycle, or hormone treatment. Depending on the dose and the ZT, ET-3 may promote an increase or inhibition of gene expression of Opn4x, Opn4m and ETc, indicating a dose-dependent modulatory effect. In addition, endothelin-3 may also act as a synchronizing agent of the melanopsins transcripts. (AU)

FAPESP's process: 09/02673-7 - Endothelin effects on gene expression of melanopsins (Opn4x and Opn4m) and of ETC receptor in Xenopus laevis melanophores
Grantee:Maria Nathália de Carvalho Magalhães Moraes Figueira Borges
Support type: Scholarships in Brazil - Master