The tiny spheres inside brain cells that ferry chemical messengers into the synapse make their rounds much more expeditiously than once assumed, National Institute of Mental Health (NIMH) - funded researchers have discovered. They used a dye to track the behavior of such synaptic vesicles in real time, in rat brain cells. Rather than fusing completely with the cell membrane and disgorging their dye contents all at once, brain vesicles more often remained intact, secreting only part of the tracer cargo in each of several repeated, fleeting contacts with the membrane, report Richard Tsien, D.Phil., Stanford University, and colleagues Alex Aravanis and Jason Pyle, in the June 5, 2003 Nature. Dubbed "kiss-and-run" recycling, this allows for more efficient communication between brain cells, suggest the researchers.
Brain cells communicate in a process that begins with an electrical signal and ends with a neurotransmitter binding to a receptor on the receiving neuron. It lasts less than a thousandth of a second, and is repeated billions of times daily in each of the human brain’s 100 billion neurons. Much of the action is happening inside the secreting cell. There, electrical impulses propel vesicles into the cell wall to spray the neurotransmitter into the synapse. Likened to soap bubbles merging, or bubbles bursting at the surface of boiling water, this process of membrane fusion (*RealPlayer format) may hold clues about what goes wrong in disorders of thinking, learning and memory, including schizophrenia and other mental illnesses thought to involve disturbances in neuronal communication.
Neurons must recycle a finite number of vesicles. In "classical" membrane fusion, the vesicle totally collapses and mixes with the cell membrane, requiring a complex and time-consuming and retrieval and recycling process. Yet, Tsien and colleagues point out that this process was discovered in huge neurons, such as those in squid giant synapses, with tens or hundreds of thousands of vesicles per nerve terminal. By contrast, they find that the comparatively tiny nerve terminals of the mammalian brain must make do with only about 30 functional vesicles – hardly enough to keep up with the split-second demands of synaptic communication if vesicles can only be replenished via the, one-shot classical process, they argue. Hence, the "kiss-and-run" hypothesis.
Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.
Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
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,...
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...
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...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering
12.12.2017 | Life Sciences