The so-called “circadian rhythm” consists in a series of biological processes that enable the brain activity to adapt to the time of the day (light and dark cycles). One of the central players in this adaptation is the pineal gland, whose function is, among others, the synthesis of melatonin, which is produced and released at night and which acts in different parts of the body regulating the metabolic activity.
Norepinephrine is a hormone involved in regulating melatonin synthesis and release in the pineal gland. The functions of norepinephrine are carried out via the binding to its receptors in the membrane of cells. It was long believed that these norepinephirne receptors acted individually. In this study researchers have discovered that norepinephirne receptors do not act independently, but forming heteromers with other proteins, with dopamine receptors. When dopamine, which is an important neurotransmitter, interacts with its receptors, it inhibits the effects of norepinephrine and decreases melatonin production and release. These dopamine receptors only appear in the pineal gland at the end of the dark period. Therefore, the formation of these heteromers is an effective mechanism to stop melatonin production when the day begins.
The discovery of this new function of the dopamine will be extremely useful when designing new treatments to help mitigate circadian rhythm disturbances such as those related to jet lag, those found among people who work at night-time and in cases of sleep disorders in general which, according to the World Health Organisation affect 40% of the worldʼs population and one third of the adult population in Spain. Circadian rhythm disturbances also produce alterations in the body mass index above the recommended levels among 50% of the European population, according to the Health at a Glance Europe 2010 report by the European Commission and the OECD, and behavioural disorders that affect 1 in 4 people at least once in their lifetime in which melatonin levels are related.
This project has been carried out by the Molecular Neurobiology Research Team of the University of Barcelona where lecturers Dr. Peter Mc Cormick, Dr. Enric Canela, Dr. Antoni Cortés, Dr. Josefa Mallol, Dr. Vicent Casadó and Dr. Carme Lluís work. Dr. David Moreno and doctoral students Sergio González and Estefanía Moreno have also taken part in it.
About CIBERNED
The Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) is one of reference centres in Spain for biomedical research on neurodegenerative diseases (NDD), such as Alzheimerʼs, Parkinsonʼs, Huntingtonʼs diseases and other ataxias and neuromuscular diseases. It was created in 2006 and its main objective is to promote basic biomedical, clinical and epidemiological research, as well as to ensure that the research carried out in laboratories can be put into practice and reach the patient (translational research).
Legally it is organised as a public consortium where various institutions representing the Spanish General State Administration, the Spanish Autonomous Communities and other non-institutional organisations take part. It gathers a total of 58 Spanish research groups that share a common goal: the fight against neurodegeneration.
The funds managed by CIBERNED come mainly from the Spanish Government, namely from the Ministry of Economy and Competitiveness, which are channelled through the Carlos III Health Institute. However, CIBERNED can raise financial support from other foundations or research funds. In addition to basic and clinical research, CIBERNED aims to promote high-quality scientific dissemination and involve civil society in reducing the negative impact of neurodegeneration.
