Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New findings may lead to treatment for anxiety in Rett Syndrome

15.11.2006
The classic form of Rett Syndrome (RTT) shows us a child who is the picture of anxiety: she wrings her hands, hyperventilates, trembles.

The sinister progression of the disorder, which usually begins to manifest between the ages of 6-18 months, includes loss of acquired skills, speech and mobility, sometimes an autistic-like withdrawal, sometimes months of inconsolable crying. A majority of girls with RTT, which is caused by mutations in the gene MECP2, display elevated stress hormones measured by urinary cortisol levels. New studies may shed light on whether much of the anxiety of these children is a response to the subjective experience of RTT, or is an intrinsic aspect of the disorder.

The lab of Huda Zoghbi at Baylor College of Medicine has been studying anxiety in their mouse model of the syndrome. These MeCP2308 mice, so called because they bear a mutant version of the MeCP2 protein that is truncated prematurely (at amino acid 308), have numerous characteristics that mimic human RTT. They appear to be healthy early on in life, but within several weeks of birth develop tremors, spasticity, seizures, and begin to display impairments in social behavior and cognitive skills. They also show signs of anxiety: they huddle in closed spaces rather than curiously exploring new areas, they avoid spending time with other animals, they tremble noticeably when being handled by the gentlest of researchers. And, as the Zoghbi lab now reports in The Proceedings of the National Academy of Sciences, the mice produce high levels of corticosterone, the mouse equivalent of the human stress hormone.

What causes the mice to be so stressed? Because MECP2 controls the expression of other genes, mutations in the protein that disrupt its normal function should allow misexpression of target genes. Thus far, five targets of MeCP2 activity have been identified, though the precise role any of them play in the RTT phenotype remains unclear. But the combination of anxious behavior and increased corticosterone release led McGill et al. to hypothesize that their mice might be suffering from abnormal expression of Crh, the gene that produces corticotropin-releasing hormone (CRH). The authors searched specific regions of the MeCP2308 mouse brain where CRH normally works, and found that the mice do indeed overexpress Crh in regions responsible for behavioral and physiological responses to stress.

In healthy mammals, CRH activates the hypothalmic-pituitary-adrenal axis in response to stressful events, stimulating glucocorticoid release from the adrenal cortex. When the environmental stressor subsides, glucocorticoid levels return to normal. Chronic stress, however, can damage neurons, reduce synaptic plasticity, and impair short-term memory -- as any stressed-out parent can attest. What is interesting here is that these same neuronal effects are seen in RTT. This suggests that an overabundance of CRH could be contributing to other aspects of the Rett phenotype.

The good news is that it is now possible to envision finding a drug that would reduce anxiety in individuals with RTT by blocking receptors for corticotropin-releasing hormone. Decreasing anxiety might also reduce some other symptoms of RTT that are produced by chronic neuronal exposure to CRH.

Monica Coenraads | EurekAlert!
Further information:
http://www.rsrf.org

More articles from Health and Medicine:

nachricht Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>