All it takes is the flip of a protein "switch" within the tiny wire-like capillaries of the brain to increase the blood flow that ensures optimal brain function. New research has uncovered that capillaries have the capacity to both sense brain activity and generate an electrical vasodilatory signal to evoke blood flow and direct nutrients to nourish hard-working neurons.
These findings were reported online in Nature Neuroscience.
When there is an increase in brain activity, there is an increase in blood flow, says Thomas Longden, Ph.D., assistant professor of pharmacology at the Larner College of Medicine at the University of Vermont and first author of the study. "The area of the brain covered by the capillaries--the smallest blood vessels in the body -- vastly surpasses the area covered by arterioles. This ideally positions them for monitoring neuronal activity and controlling blood flow."
Understanding the mechanisms that precisely direct cerebrovascular blood flow to satisfy the brain's ever-changing energy needs has, to date, eluded scientists. Neurons consume an enormous amount of the body's energy supplies -- about 20 percent -- yet lack their own reserves, so are reliant on blood to deliver nutrients.
Previously, capillaries were thought to be passive tubes and the arterioles were thought to be the source of action. Now, Longden and colleagues have discovered that capillaries actively control blood flow by acting like a series of wires, transmitting electrical signals to direct blood to the areas that need it most.
To achieve this feat, the capillary sensory network relies on a protein (an ion channel) that detects increases in potassium during neuronal activity. Increased activity of this channel facilitates the flow of ions across the capillary membrane, thereby creating a small electrical current that generates a negative charge--a rapidly transmitted signal -- that communicates the need for additional blood flow to the upstream arterioles, which then results in increased blood flow to the capillaries.
The team's study also determined that if the potassium level is too high, this mechanism can be disabled, which may contribute to blood flow disturbances in a broad range of brain disorders.
"These findings open new avenues in the way we can investigate cerebral diseases with a vascular component," says co-first author Fabrice Dabertrand, Ph.D., an assistant professor of pharmacology at the University of Vermont's Larner College of Medicine. Cerebrovascular illnesses like Alzheimer's disease, CADASIL, and other conditions that cause cognitive decline can, in part, be a consequence of neurons not receiving enough blood flow and therefore not getting sufficient nutrients.
"If you're hungry, you're not able to do your best work; it may be the same for neurons," says Dabertrand, who adds that the group's next phase of research will focus on exploring potential pathological factors involved in disabling the capillary potassium-sensing mechanism.
An image from the Vermont team's research will be featured on the cover of the May 2017 issue of Nature Neuroscience.
Jennifer Nachbur | EurekAlert!
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences