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Laboratory of Biological Rhythms

Laboratory of Biological Rhythms From the left: Central clock in the brain - the suprachiasmatic nucleus (SCN); glial cells in the SCN; lcocomotor activity records of rats; neurons in hippocampus; clock gene expression in the SCN with a phase plot.

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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?



Fig. PER2 protein in the prenatal and early postnatal SCN, ex vivo luminescence microscopy.


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



Drapšin; Milica - Dočkal; Tereza - Houdek; Pavel - Sládek; Martin - Semenovykh; Kateryna - Sumová; Alena . Circadian clock in choroid plexus is resistant to immune challenge but dampens in response to chronodisruption . Brain Behavior and Immunity. 2024; 117(March); 255-269 . IF = 15.1 [ASEP] [ doi ]
Sládek; Martin - Klusáček; Jan - Hamplová; Dana - Sumová; Alena . Population-representative study reveals cardiovascular and metabolic disease biomarkers associated with misaligned sleep schedules . Sleep. 2023; 46(6)); zsad037 . IF = 5.6 [ASEP] [ doi ]
Liška; Karolína - Dočkal; Tereza - Houdek; Pavel - Sládek; Martin - Lužná; Vendula - Semenovykh; Kateryna - Drapšin; Milica - Sumová; Alena . Lithium affects the circadian clock in the choroid plexus – A new role for an old mechanism . Biomedicine & Pharmacotherapy. 2023; 159(March)); 114292 . IF = 7.5 [ASEP] [ doi ]
Honzlová; Petra - Sumová; Alena . Metabolic regulation of the circadian clock in classically and alternatively activated macrophages . Immunology and Cell Biology. 2023; 101(5); 428-443 . IF = 4.0 [ASEP] [ doi ]
Honzlová; Petra - Semenovykh; Kateryna - Sumová; Alena . The Circadian Clock of Polarized Microglia and Its Interaction with Mouse Brain Oscillators . Cellular and Molecular Neurobiology. 2023; 43(3); 1319-1333 . IF = 4.0 [ASEP] [ doi ]

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Prof. PharmDr. Alena Sumová, DSc.

Head of the Laboratory  ORCID iD icon

Martin Sládek, PhD.

Deputy Head of the Laboratory

prof. Helena Illnerová

professor emeritus

RNDr. Pavel Houdek


Milica Drapšin

PhD student

Fyziologický ústav AV ČR - Vývojová kardiologie

Dmytro Semenovykh 

PhD student

Kateryna Semenovykh

PhD student

Tereza Dočkal

PhD student

Eva Tlustá