The effects of melatonin on the activity of the c-fos gene in the structures of the hypothalamic paraventricular nucleus under prolonged lighting

Keywords: lateral magnocellular subnuclei; gene expression; c-Fos protein; photoperiod


The effect of constant illumination as a stress factor on the state of the "early response" c-fos gene in the lateral magnocellular subnuclei of the paraventricular nucleus (lmPVN) of the hypothalamus of rats at different time intervals (day and night) has been studied. To identify c-Fos in histological sections of the hypothalamus, a secondary (indirect) immunofluorescence method is used. Expression of the product of this gene, the c-Fos protein, in animals kept under normal conditions of alternation of illumination and darkness, shows a clear-cut circadian character. There was a significant decrease in the area of the immunopositive sites of structures at night by 19.4% compared to daytime measurements. The average values of the areas of such immunopositive subnuclei sites varied also in subgroups of rats under light stimulation conditions, in which samples of lmPVN were selected for study at 2 pm and 2 am, but the differences between groups did not reach the level of reliability. Under conditions of light stress, the c-Fos concentration index decreased by 29.4% during the day, and by 16.5% at night in relation to similar values in the intact group. In animals that were in the standard light mode, the c-Fos protein concentration index was significantly higher during the day than at night. In the intact group, the night value of the c-Fos concentration index averaged only 71.5% of the daily value. In rats subjected to constant illumination, the day and night values of the c-Fos concentration index did not differ reliably. To correct stress-induced changes in the activity of the "early response" c-fos gene in the rat hypothalamus, melatonin (0.5 mg/kg body weight of the animal) was used. Injections of melatonin to rats exposed to constant illumination normalized the circadian rhythm of the area of the material immunoreactive to c-Fos, compared to the group of animals that did not receive melatonin. When using melatonin against the background of constant illumination, a sharp increase of the protein concentration in the lmPVN subnuclei of hypothalamus in daytime and less pronounced at night intervals was detected. Injections of melatonin to animals were also reflected in the daily dynamics of the index of c-Fos protein content in the lmPVN subnuclei under conditions of constant illumination. In the daytime observation period, the index was almost twice the experimental data on stressed animals without the introduction of the hormone, bringing it closer to normal. Prospects for further research in this sphere will allow us to better understand the place and role of subnuclei of paraventricular nuclei of the hypothalamus in the mechanisms of the formation of circadian rhythms of the rat brain.


Abreu, T., & Bragança, M. (2015). The bipolarity of light and dark: A review on bipolar disorder and circadian cycles. Journal of Affective Disorders, 185, 219–229.

Arushanyan, E. B., & Shchetinin, E. V. (2016). Melatonin kak universal'nyy modulyator lyubykh patologicheskikh protsessov [Melatonin as a universal modulator of any pathological processes]. Patologicheskaya Fiziologiya i Eksperimental'naya Terapiya, 60(1), 79–88 (in Russian).

Bains, J. S., Wamsteeker Cusulin, J. I., & Inoue, W. (2015). Stress-related synaptic plasticity in the hypothalamus. Nature Reviews Neuroscience, 16(7), 377–388.

Bedont, J. L., & Blackshaw, S. (2015). Constructing the suprachiasmatic nucleus: A watchmaker’s perspective on the central clockworks. Frontiers in Systems Neuroscience, 9, 74.

Bedont, J. L., Newman, E. A., & Blackshaw, S. (2015). Patterning, specification, and differentiation in the developing hypothalamus. Wiley Interdisciplinary Reviews. Developmental Biology, 4(5), 445–468.

Chun, L. E., Christensen, J., Woodruff, E. R., Morton, S. J., Hinds, L. R., & Spen cer, R. L. (2017). Adrenal-dependent and independent stress-induced Per1 mRNA in hypothalamic paraventricular nucleus and prefrontal cortex of male and female rats. Stress, 22, 1–15.

Daubert, D. L., Looney, B. M., Clifton, R. R., Cho, J. N., & Scheuer, D. A. (2014). Elevated corticosterone in the dorsal hindbrain increases plasma norepineph rine and neuropeptide Y, and recruits a vasopressin response to stress. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 307(2), R212–224.

Erren, T. C., & Reiter, R. J. (2015). Melatonin: A universal time messenger. Neu roеndocrinology Letters, 36(3), 187–192.

Fan, S., Dakshinamoorthy, J., Kim, E. R., Xu, Y., Huang, C., & Tong, Q. (2016). An indirect action contributes to c-fos induction in paraventricular hypothalamic nucleus by neuropeptide Y. Scientific Reports, 6, 19980.

Flak, J. N., Myers, B., Solomon, M. B., McKlveen, J. M., Krause, E. G., & Her man, J. P. (2014). Role of paraventricular nucleus-projecting norepinephri ne/epinephrine neurons in acute and chronic stress. European Journal of Neu roscience, 39(11), 1903–1911.

Franco, A. J., Chen, C., Scullen, T., Zsombok, A., Salahudeen, A. A., Di, S., Herman, J. P., & Tasker, J. G. (2016). Sensitization of the hypothalamic-pituitary-adrenal axis in a male rat chronic stress model. Endocrinology, 157(6), 2346–2355.

Furlong, T. M., McDowall, L. M., Horiuchi, J., Polson, J. W., & Dampney, R. A. (2014). The effect of air puff stress on c-Fos expression in rat hypothalamus and brainstem: Central circuitry mediating sympathoexcitation and barore flex resetting. European Journal of Neuroscience, 39(9), 1429–1438.

Herman, J. P., McKlveen, J. M., Ghosal, S., Kopp, B., Wulsin, A., Makinson, R., Scheimann, J., & Myers, B. (2016). Regulation of the hypothalamic-pituitary-adrenocortical stress response. Comprehensive Physiology, 6(2), 603–621.

Houdek, P., & Sumová, A. (2014). In vivo initiation of clock gene expression rhythmicity in fetal rat suprachiasmatic nuclei. PLoS One, 9(9), e107360.

Inta, I., Bettendorf, M., & Gass, P. (2016). Conserved hypothalamic c-fos activation pattern induced by the MGLU5 receptor antagonist MPEP during peri-pubertal development in mice. Pharmacopsychiatry, 49(4), 142–145.

Kobayashi, Y., Ye, Z., & Hensch, T. K. (2015). Clock genes control cortical criti cal period timing. Neuron, 86(1), 264–275.

Kozaki, T., Kubokawa, A., Taketomi, R., & Hatae, K. (2015). Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night. Journal of Physiological Anthropology, 34(1), 27.

Lacoste, B., Angeloni, D., Dominguez-Lopez, S., Calderoni, S., Mauro, A., Fras chini, F, Descarries, L., & Gobbi, G. (2015). Anatomical and cellular locali zation of melatonin MT1 and MT2 receptors in the adult rat brain. Journal of Pineal Research, 58(4), 397–417.

Miklos, Z., Flynn, F., & Lessard, A. (2014). Stress-induced dendritic internalization and nuclear translocation of the neurokinin-3 (NK3) receptor in vasopressin ergic profiles of the rat paraventricular nucleus of the hypothalamus. Brain Research, 1590, 31–44.

Miyake, H., Mori, D., Katayama, T., Fujiwara, S., Sato, Y., Azuma, K., & Kubo, K. Y. (2016). Novel stress increases hypothalamic-pituitary-adrenal activity in mice with a raised bite. Archives of Oral Biology, 68, 55–60.

Ordyan, N. E., Pivina, S. G., Rakitskaya, V. V., & Akulova, V. K. (2016). Harak teristika aktivnosti gipotalamo-gipofizarno-nadpochechnikovoj sistemy pre natal'no stressirovannyh samcov krys v jeksperimental'noj modeli depressii [Activity of hypothalamic-pituitary-adrenal axis of prenatally stressed male rats in experimental model of depression]. Zhurnal Evoliutsionnoi Biokhimii і Fiziologii, 52(1), 51–57 (in Russian).

Reiter, R. J., Tan, D. X., & Galano, A. (2014). Melatonin: Exceeding expectations. Physiology (Bethesda), 29(5), 325–333.

Robinson, I., & Reddy, A. (2014). Molecular mechanisms of the circadian clock work in mammals. FEBS Letters, 588(15), 2477–2483.

Toshinai, K., Saito, T., Yamaguchi, H., Sasaki, K., Tsuchimochi, W., Minamino, N., Ueta, Y., & Nakazato, M. (2014). Neuroendocrine regulatory peptide-1 and -2 (NERPs) inhibit the excitability of magnocellular neurosecretory cells in the hypothalamus. Brain Research, 1563, 52–60.

Tymofii, O. V., Bulyk, R. Y., & Lomakina, Y. V. (2015). Efekty melatoninu na ekspresiiu hena c-Fos u neironakh medial'noho dribnoklitynnoho sub’iadra paraventrykuliarnoho yadra hipotalamusa schuriv pry zminenomu fotoperiodi [Melatonin’s effects on the c-fos gene expression in neurons of the medial small subnucleus of hypothalamus paraventricular nucleus of rats under alte red light condition]. Svit Medytsyny ta Biolohii, 2(50), 187–191 (in Ukrainian).

Wang, J. L., Lim, A. S., Chiang, W. Y., Hsieh, W. H., Lo, M. T., Schneider, J. A., Buchman, A. S., Bennett, D. A., Hu, K., & Saper, C. B. (2015). Suprachias matic neuron numbers and rest-activity circadian rhythms in older humans. Annals of Neurology, 78(2), 317–322.

Zamorskiy, I. I., Sopova, I. Y., & Khavinson, V. K. (2012). Vliyanie melatonina i epitalamina na soderzhanie produktov belkovoy i lipidnoy peroksidatsii v kore bol'shikh polushariy i gippokampe mozga krys v usloviyakh ostroy gipoksii [Effects of melatonin and epithalamin on the content of protein and lipid peroxidation products in rat cortex and hippocampus under conditions of acute hypoxia]. Byulleten' Eksperimental'noy Biologii i Meditsiny, 154(7), 59–61 (in Russian).

How to Cite
Bulyk, R. Y., Abramov, A. V., Bulyk, T. S., Kryvchanska, M. I., & Vlasova, K. V. (2018). The effects of melatonin on the activity of the c-fos gene in the structures of the hypothalamic paraventricular nucleus under prolonged lighting. Regulatory Mechanisms in Biosystems, 9(2), 131-134.