Sleep is viewed by many in the scientific and medical community as a complex but fascinating phenomenon. Many humans and other living creatures undertake this process for most of their lives, but to date there are still elements of the sleep process that are yet to be understood. A group of biologists at Caltech have been able to locate the gene, neuromedin U(Nmu) which may be able to improve the current understanding of sleep regulation from wakefulness to the promotion of sleep. The Caltech biologists found that if this particular gene was over activated in the animals that were studied this lead to severe insomnia. In a paper published in the February 2016 issue of Neuron, Prof. Prober and his Caltech colleagues found that this gene may be viewed as nature’s stimulant and given that sleep is a common process for most humans and other living things, we still do not fully understand this complex but commonly experienced process. The biologists undertook their research with the use of genetic screens can help to better understand the sleep process for organism with simplistic anatomies but it proves to be more of a challenge in vertebrates due to the complex anatomies and limited potential for duplication.
Luckily, the zebrafish have come to be viewed as valuable vertebrate model for evaluating sleep and it was identified that there are similarities between the anatomy of zebrafish and mammalian brains that suggest some of the basic neural circuits that can be involved in the regulation of sleep. In the researchers study of the zebrafish a gain-of-function approach was used which meant that when the zebrafish were single cells they were injected with DNA molecule that had a gene that was placed into the genome of a few of the cells in each fish. They wanted to test the genes (neuropeptides) which have been implicated in the sleep process. The biologist were able to control the expression of the inserted gene using a heat-shock promoter that activates when the fish was heated to 37 degrees Celsius. It allows for the overexpression of the gene and the use of video trackers were used to monitor the fish over days to see which affected sleep.
Ultimately, the researchers were able to find that the most notable change was that of the overexpression of the NMU, which can also be found in mammals in the hypothalamus. In order to understand the role of NMU in the sleep process, they looked at the hypothalamic-pituitary-adrenal (HPA) axis and NMU’s involvement in its activation. The researchers were able to find that NMU suppressed sleep to the same degree in zebrafish mutants that did not have the protein, glucocorticoid receptor that is necessary for the HPA axis signaling. While the many wake-promoting and sleep promoting genes have been identified scientists still have to identify which ones are important for causing specific sleep disorders in humans and how this can help with treatment.
EurekAlert (2016). Caltech biologists identify gene that helps regulate sleep. Retrieved from http://www.eurekalert.org/pub_releases/2016-02/ciot-cbi021716.php
Author: Dr. Abimbola Farinde, PharmD –
Dr. Farinde is a healthcare professional who has gained experience in the field and practice of psychopharmacology/mental health, and geriatric pharmacy. She has worked with active duty soldiers with dual diagnoses of a traumatic brain injury and a psychiatric disorder providing medication therapy management and disease state management.