Estrogens like estradiol are crucial in modulating neural circuits that govern such behaviors as feeding and reproduction, memory, cognition and neuroplasticity in animals and humans.
In a series of experiments with zebra finches, Remage-Healey and neuroendocrinologists from the University of California Los Angeles (UCLA) provide a new picture of neuron-produced estradiol suggesting that it acts remarkably like a classic neurotransmitter controlled by electrochemical events, in addition to its role as a hormone in the bloodstream, he adds.
“The fact that the brain synthesizes estradiol at the synapse in a very rapid, targeted way makes it almost a different beast than the estradiol we knew before. So we now know the brain can produce its own supply of estrogens that are not really acting like hormones anymore, but more like neurotransmitters. It’s the exact same molecule in birds, fish, dogs and humans. It’s the same molecule as is produced in the human ovary. But now we know that neurons can control the release of estrogens onto other neurons, in a way similar to the way neurotransmitters are controlled.”
These new findings also support the idea that neuroestrogens modulate information flow in the brain’s cortex in seconds to minutes, in contrast to the hours and days it takes for hormones circulating in the blood stream to have an effect. This work supported by the National Institutes of Health is described in a July issue of the Journal of Neuroscience.
“It’s clear now that neurons are producing estrogens in presynaptic terminals, the hand-shake zone where a signal between neurons is transmitted,” says Remage-Healey. He adds that these findings are extremely exciting because “presynaptic terminals are the interface between neurons. When that connection is strengthened in the presence of estradiol, it could lead to enhanced learning and plasticity.”
For these experiments, the UMass Amherst and UCLA researchers developed a microdialysis probe to conduct in vivo real-time testing in the forebrains of active, alert zebra finches. These robust little birds are awake and flying, singing, eating and drinking with a tiny micron-diameter probe implanted in their forebrains. The probe not only allows researchers to measure estradiol levels but to alter local potassium and calcium levels, chemicals that activate or inhibit neural activity.
In a clever twist, Remage-Healey and colleagues also use conotoxin, a very specific toxin produced by the cone snail. It targets only presynaptic nerve terminals that use a voltage-gated calcium channel. The researchers pump minute amounts of the toxin through the probe to precisely inhibit calcium channels in individual nerve terminals. In this way, they established that estradiol is calcium-dependent, is synthesized very rapidly in response to stimuli in the presynaptic terminal, but not in the neuronal cell body.
In a typical experiment, Remage-Healey and colleagues infuse artificial cerebrospinal fluid through the probe continuously over a 30-minute period. They receive back dialysate, from which they measure local estradiol concentration. Results challenge the traditional view that the brain is responding to estrogens produced elsewhere.
The UMass Amherst neuroestrogen expert adds, “In other experiments using this new technology we’ve shown that estradiol is changing in this same brain area when the animal hears a sound. This shows that estradiol is fluctuating much faster and in a more specific way than we understood before. Estrogens could therefore target their actions to certain neurons, synapse by synapse.”
Overall, the new findings could open the path to investigate more precisely the role of estrogens in learning, and perhaps reveal a way to deliver estradiol directly to neurons to enhance cognitive abilities without systemic side effects such as increased heart disease risk.Luke Remage-Healey
Luke Remage-Healey | Newswise Science News
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction