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Neurohumoral Regulations

Neurohumoral Regulations Central clock in the brain - the suprachiasmatic nucleus. A cross section of the brain at the level of the hypothalamus is shown. Immunohistochemistry (bright field on the left and fluorescence on the right) was used to detect clock cells.

In the center of our interest is the endogenous time-keeping system, circadian clock of mammals, including humans. The system temporally regulates rhythmic processes in our body so that they take place at the proper time of day and are optimally synchronized relative to each other.

A failure of the temporal regulation has a negative impact on human health. Using in vivo and in vitro models, we study the molecular mechanisms underlying the circadian clock as well as the resulting physiological and behavioral rhythms.

We focus on the following questions:

  • What are the mechanisms for entraining (synchronizing) the circadian system and what are the consequences of its failure?
  • How does the circadian system develop and how is it being entrained during ontogeny?
  • How is the circadian system of humans entrained in real life conditions, both in health and in disease?


The ontogenesis of the biological clock of laboratory rat

The mammalian biological clock initiates its ontogenesis already during embryonic development in the maternal uterus. Newborn mammals are equipped with clock running in accordance with the maternal clock. We focus on investigating when and how do the newborn clock develop and entrain.  More



Polidarová, Lenka - Sládek, Martin - Novosadová, Zuzana - Sumová, Alena . Aging does not compromise in vitro oscillation of the suprachiasmatic nuclei but makes it more vulnerable to constant light . Chronobiology International. 2017, roč. 34, 1, p. 105-117 . IF = 2.562 [ASEP] [ doi ]
Polidarová, Lenka - Houdek, Pavel - Sumová, Alena . Chronic disruptions of circadian sleep regulation induce specific proinflammatory responses in the rat colon . Chronobiology International. 2017, roč. 34, 9, p. 1273-1287 . IF = 2.562 [ASEP] [ doi ]
Polidarová, Lenka - Houdek, Pavel - Sládek, Martin - Novosadová, Zuzana - Pácha, Jiří - Sumová, Alena . Mechanisms of hormonal regulation of the peripheral circadian clock in the colon . Chronobiology International. 2017, roč. 34, 1, p. 1-16 . IF = 2.562 [ASEP] [ doi ]
Májovský, M. - Řezáčová, Lenka - Sumová, Alena - Pospíšilová, L. - Netuka, D. - Bradáč, O. - Beneš, V. Melatonin and cortisol secretion profile in patients with pineal cyst before and after pineal cyst resection . Journal of Clinical Neuroscience. 2017, roč. 39, May 2017, p. 155-163 . IF = 1.557 [ASEP] [ doi ]
Weissová, Kamila - Bartoš, A. - Sládek, Martin - Nováková, Marta - Sumová, Alena . Moderate Changes in the Circadian System of Alzheimer's Disease Patients Detected in Their Home Environment . PLoS ONE. 2016, roč. 11, 1, e0146200 . IF = 2.806 [ASEP] [ doi ]

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Institute of Physiology AS CR, v.v.i.
Department of Neurohumoral Regulations

Vídeňská 1083
14220 Prague 4
Czech Republic
tel. +420 241 062 528
fax. +420 241 062 488


Doc. PharmDr. Alena Sumová, DSc.

head of the department

Martin Sládek, PhD.
deputy head of the department

Prof. Helena Illnerová, DrSc.
Lenka Polidarová, PhD.
Pavel Houdek

research assistant


Zuzana Novosadová

PhD student

Karolína Šuchmanová

PhD student


Vendula Čečmanová

PhD student


Petra Honzlová

PhD student

  Lucie Heppnerová
  Eva Suchanová