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 Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>