Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Find New Actions of Neurochemicals

03.07.2009
Although the tiny roundworm Caenorhabditis elegans has only 302 neurons in its entire nervous system, studies of this simple animal have significantly advanced our understanding of human brain function because it shares many genes and neurochemical signaling molecules with humans.

Now MIT researchers have found novel C. elegans neurochemical receptors, the discovery of which could lead to new therapeutic targets for psychiatric disorders if similar receptors are found in humans.

Dopamine and serotonin are members of a class of neurochemicals called biogenic amines, which function in neuronal circuitry throughout the brain. Many drugs used to treat psychiatric disorders, including depression and schizophrenia, target these signaling systems, as do cocaine and other drugs of abuse. Scientists have long known of a class of biogenic-amine receptors that are G protein-coupled receptors (GPCRs) and that, when activated, trigger a slow but long-lasting cascade of intracellular events that modulate nervous system activity.

A study in the July 3 issue of Science has found that in C. elegans these chemicals also act on receptors of a fundamentally different type. These receptors are chloride channels that open and close quickly in response to the binding of a neurochemical messenger. By allowing the passage of negatively charged chloride ions across the cell membrane, chloride channels can rapidly inactivate nerve cells.

"These results underscore the importance of determining whether, as in the C. elegans nervous system, a diversity of biogenic amine-gated chloride channels function in the human brain,” said H. Robert Horvitz of the McGovern Institute for Brain Research at MIT and senior author of the study. “If so, such channels might define novel therapeutic targets for neuropsychiatric disorders, such as depression and schizophrenia."

In 2000, Horvitz’s group discovered that serotonin activates a chloride channel they called MOD-1, which inhibits neuronal activity in C. elegans.

In the current study, Niels Ringstad and Namiko Abe, a postdoctoral researcher and an undergraduate in Horvitz’s laboratory, respectively, looked for other ion channels that could be receptors for biogenic amines. Using both in vitro and in vivo methods, they surveyed the functions of 26 ion channels similar to MOD-1 and found three additional ion channels with an affinity for biogenic amines: dopamine activates one, serotonin another, and tyramine (the role of which in the human brain is unknown) a third. All three were chloride channels, like MOD-1.

“We now have four members of a family of chloride channels that can act as receptors for biogenic amines in the worm,” Ringstad said. “That these neurochemicals activate both GPCRs and ion channels means that they can have very complex actions in the nervous system, both as slow-acting neuromodulators and as fast-acting inhibitory neurotransmitters.”

It is unknown as yet whether an equivalent to this new class of worm receptor exists in the human brain, but Horvitz points out that worms have proved remarkably informative for providing insights into human biology. In 2002, Horvitz shared the Nobel Prize in Physiology or Medicine for the discovery based on studies of C. elegans of the mechanism of programmed cell death, a central feature of some neurodegenerative diseases and many other disorders in humans.

“Historically, studies of C. elegans have delineated mechanisms of neurotransmission that subsequently proved to be conserved in humans,” says Horvitz, the David H. Koch Professor of Biology at MIT and a Howard Hughes Medical Institute Investigator. “The next step is to look for chloride channels controlled by biogenic amines in mammalian neurons.”

This study was supported by the NIH, the Howard Hughes Medical Institute, the Life Sciences Research Foundation, and The Medical Foundation.

Broadcast quality video is available upon request.

Elizabeth Thomson | Newswise Science News
Further information:
http://www.mit.edu

More articles from Life Sciences:

nachricht Closing in on advanced prostate cancer
13.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Visualizing single molecules in whole cells with a new spin
13.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>