In a study available online in the Proceedings of the National Academy of Sciences, scientists from UT Southwestern show that the Clock gene, which controls the body’s circadian rhythms, may be integrally involved in the development of bipolar disorder. Circadian rhythms include the daily ups-and-downs of waking, eating and other processes such as body temperature, hormone levels, blood pressure and heart activity.
The study included putting the mutant mice through a series of tests, during which they displayed hyperactivity, decreased sleep, decreased anxiety levels, a greater willingness to engage in “risky” activities, lower levels of depression-like behavior and increased sensitivity to the rewarding effects of substances such as cocaine and sugar.
“These behaviors correlate with the sense of euphoria and mania that bipolar patients experience,” said Dr. McClung. “In addition, there is a very high co-morbidity between drug usage and bipolar disorder, especially when patients are in the manic state.”
During the study, lithium was given to the mutant mice. Lithium, a mood-stabilizing medication, is most commonly used in humans to treat bipolar patients. Once treated with the drug on a regular basis, the majority of the study’s mice reverted back to normal behavioral patterns, as do humans.
The researchers also injected a functional Clock gene protein — basically giving the mice their Clock gene back – into a specific region of the brain that controls reward functions and where dopamine cells are located. Dopamine is a neurotransmitter associated with the “pleasure system” of the brain and is released by naturally rewarding experiences such as food, sex and the use of certain drugs. This also resulted in the mice going back to normal behaviors.
“While the Clock gene is expressed throughout the brain, it’s really only been studied in one particular brain region, which is the one that’s involved in circadian rhythms,” said Dr. McClung. “This is one of the first studies to show that Clock has a major effect on behavior in a different brain region — specifically the one that controls reward responses and mood.”
Dr. Eric Nestler, chairman of UT Southwestern’s psychiatry department and also a study author, said the research is important because it establishes the first complete mouse model for studying bipolar disorder.
“The lack of an animal model for bipolar disorder has been a crucial limitation in our efforts to better understand the biological basis of the disorder,” said Dr. Nestler, who holds the Lou and Ellen McGinley Distinguished Chair in Psychiatric Research. “Dr. McClung’s findings are therefore very important for the field and provide fundamentally new directions for one day developing improved treatments.”
Other researchers from UT Southwestern’s psychiatry department contributing to the study were: Dr. Shari Birnbaum, assistant professor; Dr. Sumana Chakravarty, assistant instructor; Dr. Scott Russo, postdoctoral research fellow; research technicians Ami Graham, Joseph Peevey and Kole Roybal; and Vaishnav Krishnan, MSTP student. Researchers from Harvard University, the Veterans Affairs North Texas Health Care System, Northwestern University and Howard Hughes Medical Institute also contributed.
The study was supported by grants from the National Institute on Drug Abuse and the National Institute of Mental Health.
Donna Steph Hansard | EurekAlert!
What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society
Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy