Melanin-concentrating hormone is not involved in luminescence emission in the velvet belly lanternshark, Etmopterus spinax
Luminous deep-sea etmopterid sharks use hormonal control to regulate bioluminescence. Melatonin and prolactin trigger light emission and, conversely, α-melanocyte stimulating hormone actively reduces ongoing luminescence. Interestingly, these hormones are also known as regulators of skin pigment motion in teleost fish and epipelagic elasmobranchs. On the other hand, the melanin-concentrating hormone (MCH) is another regulator of the skin pigment motion in fish melanophores. Here, we studied the putative effect of MCH on the light emission control of the velvet belly lanternshark, Etmopterus spinax (Etmopteridae). In parallel, the presence of the MCH receptor in our model is investigated through database searches. Our results show that MCH is not involved in the bioluminescence triggering in the velvet belly lanternshark. Moreover, no MCH receptor transcript was found in a specific transcriptome of the luminous ventral skin of E. spinax.
Authors would like to thank T. Sorlie from the Espegrend Marine Biological Station (University of Bergen, Norway) for the help during E. spinax collection. L.D. is Ph.D. student funded by a FRIA fellowship (F.R.S.-FNRS Belgium). J.D. is postdoctoral researcher at the University de Mons (UMONS) and he is supported by a WISD-PDR Grant from the National Funds for Research (F.R.S.-FNRS Belgium, Project number 29101409). J.M. is Research Associate of the F.R.S.-FNRS.
LD performed, analysed and interpreted the pharmacological tests, performed transcriptome data analysis and was a major contributor in writing the manuscript. JD performed transcriptome and phylogenetic analyses, contributed to and revised the manuscript. JM supervised the work, contributed to and revised the manuscript. All authors read and approved the final manuscript.
This work was supported by a Grant from the Fonds de la Recherche Scientifique (FRIA/F.R.S.-FNRS, Belgium) to L.D.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted (Animal Ethics Committee of the Catholic University of Louvain in Louvain-la-Neuve, in agreement with the European directive 2010/63/UE).
- Baker BI (1993) The role of melanin-concentrating hormone in color change. Ann N Y Acad Sci 680:279–289. https://doi.org/10.1111/j.1749-6632.1993.tb19690.x CrossRefPubMedGoogle Scholar
- Claes JM, Mallefet J (2009a) Bioluminescence of sharks: first synthesis. In: Meyer-Rochow V (ed) Bioluminescence in focus—a collection of illuminating essays. Research Signpost, Thiruvananthapuram, pp 51–65Google Scholar
- Matsuda K, Shimakura S, Maruyama K, Miura T, Uchiyama M, Kawauchi H, Shioda S, Takahashi A (2006) Central administration of melanin-concentrating hormone (MCH) suppresses food intake, but not locomotor activity, in the goldfish, Carassius autatus. Neurosci Lett 399:259–263. https://doi.org/10.1016/j.neulet.2006.02.005 CrossRefPubMedGoogle Scholar
- Mizusawa K, Amiya N, Yamaguchi Y, Takabe S, Amano M, Breves JP, Fox BK, Grau EG, Hyodo S, Takahashi A (2012) Identification of mRNAs coding for mammalian-type melanin-concentrating hormone and its receptors in the scalloped hammerhead shark Sphyrna lewini. Gen Comp Endocrinol 179(1):78–87. https://doi.org/10.1016/j.ygcen.2012.07.023 CrossRefPubMedGoogle Scholar
- Mizusawa K, Kobayashi Y, Yamanome T, Saito Y, Takahashi A (2013) Interrelation between melanocyte-stimulating hormone and melanin-concentrating hormone in physiological body color change: roles emerging from barfin flounder Verasper moseri. Gen Comp Endocrinol 181:229–234. https://doi.org/10.1016/j.ygcen.2012.09.026 CrossRefPubMedGoogle Scholar
- Sailer AW, Sano H, Zeng Z, McDonald TP, Pan J, Pong S-S, Feighner SD, Tan CP, Fukami T, Iwaasa H, Hreniuk DL, Morin NR, Sadowski SJ, Ito M, Bansal A, Ky B, Figueroa DJ, Jiang Q, Austin CP, MacNeil DJ, Ishihara A, Ihara M, Kanatani A, Van der Ploeg LHT, Howard AD, Liu Q (2001) Identification and characterization of a second melanin-concentrating hormone receptor, MCH-2R. Proc Natl Acad Sci USA 98(13):7564–7569. https://doi.org/10.1073/pnas.121170598 CrossRefPubMedGoogle Scholar
- Saito Y, Nagasaki H (2008) The melanin-concentrating hormone system and its physiological functions. In: Civelli O, Zhou QY (eds) Orphan G protein-coupled receptors and novel neuropeptides. Results and problems in cell differentiation, vol 46. Springer, Berlin, pp 159–179. https://doi.org/10.1007/400_2007_052 CrossRefGoogle Scholar
- Sherbrooke WC, Hadley ME, Castrucci AML (1988) Melanotropic peptides and receptors: an evolutionary perspective in vertebrate physiological color change. In: Hadley ME (ed) Melanotropic peptides, vol 2. CRC Press, Washington, pp 175–190Google Scholar
- Vallarino M, Andersen AC, Delbende C, Ottonello I, Eberle AN, Vaudry H (1989) Melanin-concentrating hormone (MCH) immunoreactivity in the brain and pituitary of the dogfish Scyliorhinus canicula. Colocalization with alpha-melanocyte-stimulating hormone (α-MSH) in hypothalamic neurons. Peptides 10(2):375–382. https://doi.org/10.1016/0196-9781(89)90046-6 CrossRefPubMedGoogle Scholar
- Visconti MA, Ramanzini GC, Camargo CR, Castrucci AML (1999) Elasmobranch color change: a short review and novel data on hormone regulation. J Exp Zool 284:485–491. https://doi.org/10.1002/(SICI)1097-010X(19991001)284:5%3c485:AID-JEZ3%3e3.0.CO;2-5 CrossRefPubMedGoogle Scholar