Circadian Rhythm

The circadian rhythm is a fundamental biological process that governs the timing of various physiological and behavioural events in an approximately 24-hour cycle. It is driven by an internal biological clock, located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The circadian rhythm influences a wide range of processes in the body and has significant functions in neuroscience, affecting brain function, cognition, mood, and overall health. The circadian rhythm is regulated by a complex network of molecular and cellular mechanisms. The SCN receives input from the retina regarding the light-dark cycle, helping synchronize the internal clock to the external environment. The SCN then sends signals to various brain regions and peripheral tissues, coordinating their activities in a rhythmic manner. One of the critical functions of the circadian rhythm is the regulation of the sleep-wake cycle. The internal clock promotes wakefulness during the day and initiates sleepiness at night. The central components of the internal circadian clock are a set of clock genes. These include: 1) CLOCK, which acts as a transcription factor; 2) BMAL1 (ARNTL) which forms a complex with CLOCK to activate transcription; 3) Period (PER1, PER2, PER3), which inhibit the CLOCK-BMAL1 complex; 4) cryptochrome (CRY1, CRY2), which also inhibits the CLOCK-BMAL1 complex. The CLOCK-BMAL1 complex activates the transcription of Per and Cry genes, leading to the production of PER and CRY proteins. As the levels of PER and CRY proteins increase, they form a complex and translocate to the nucleus inhibiting the CLOCK-BMAL1 complex, leading to a decrease in their own expression in a negative feedback loop. As PER and CRY proteins degrade over time, the inhibition is lifted, allowing the CLOCK-BMAL1 complex to again activate the transcription of Per and Cry genes, leading to the cyclic expression of clock genes with a period close to 24 hours, driving the circadian rhythm. The circadian clock also receives input from external cues, such as light and temperature, through specialized pathways. The most crucial input comes from the light-sensitive cells in the retina that project to the suprachiasmatic nucleus (SCN) of the hypothalamus. Light exposure received by the SCN helps to synchronize the internal circadian clock with the external environment. The circadian clock exerts control over various physiological and behavioural processes through output pathways that involve clock-controlled genes that regulate the timing of specific physiological functions, including hormone secretion, sleep-wake cycles, body temperature, and metabolism. The circadian rhythm also plays a role in memory consolidation and learning. Memory performance for example varies depending on the time of day, with optimal performance occurring during the peak of the circadian rhythm. The circadian rhythm further influences other aspects of brain function, including attention and problem-solving abilities and regulates the secretion of various hormones, including cortisol, melatonin, and growth hormone. Finally, the circadian rhythm influences the release of neurotransmitters in the brain, affecting neural communication and synaptic plasticity. For example, the levels of certain neurotransmitters, such as dopamine and serotonin, follow a circadian pattern. We provide a comprehensive product catalogue of research reagents for investigating circadian rhythm, including NPY2R antibodies, PER2 antibodies, and Cryptochrome I antibodies. Explore our full circadian rhythm product range below and discover more, for less. Alternatively, you can explore our Receptors and Hormones product ranges.