The autonomic nervous system, which is the part of the nervous system beyond conscious control, plays an important role in the release of insulin from beta cells in the endocrine part of the pancreas. The process by which this occurs has been a mystery, since it is difficult to give detailed study to such an inaccessible organ. However, researchers at Karolinska Institutet in Sweden have now managed to graft beta cells into the eyes of mice in order to study them in a living organism over a prolonged period of time. As a result, the group and a team of colleagues from the University of Miami have gained detailed knowledge of how the autonomic nervous system regulates beta-cell insulin secretion.
For this study, a technique of transplanting beta cells to the anterior chamber of the mouse eye was used. This technique was previously developed by Professor Per-Olof Berggren's group at Karolinska Institutet. In the anterior chamber of the eye the beta cells receive a supply not only of blood vessels, but also of nerves from the sympathetic and parasympathetic system, which constitute the autonomic nervous system. Put simply, the sympathetic nervous system can be said to prepare us for flight; one way it does this is to boost our energy by reducing insulin release and increasing glycogen, and consequently blood glucose. The parasympathetic nervous system operates in the reverse direction when we are at rest.
Now, the teams from Karolinska Institutet and the University of Miami have shown for the first time how the autonomic nervous system controls the beta cells and influences the regulation of blood glucose in living animals.
Using fluorescent markers for different types of nerves in combination with advanced microscopy, the researchers were able to probe the animals' eyes to study in detail the contact between the nerves and the beta cells. When the pupil contracted on exposure to light, the animals' blood glucose levels plummeted as a direct result of the stimulation of the parasympathetic nervous system. Conversely, when the pupil dilated in darkness and activated the sympathetic nervous system, their blood glucose levels rose. They also managed to influence the animals' blood glucose levels by inhibiting or stimulating each set of nerves with different substances applied directly into the eye.
"We now understand the fundamentals of how insulin secretion works and is affected by the autonomic nervous system," says Per-Olof Berggren. "The next step is to see if it works in the same way in people with diabetes or if there are defects in the signalling relevant to the disease pathogenesis."
'Noninvasive in vivo model demonstrating the effects of autonomic innervation on pancreatic islet function', Rayner Rodriguez-Diaz, Stephan Speier, Ruth Damaris Molano, Alexander Formoso, Itai Gans, Midhat H. Abdulreda, Over Cabrera, Judith Molina, Alberto Fachado, Camillo Ricordi, Ingo Leibiger, Antonello Pileggi, Per-Olof Berggren and Alejandro Caicedo, Proceedings of the National Academy of Sciences (PNAS), Online Early Edition 10-14 December 2012.
Karolinska Institutet: http://info.ki.se/ki
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
The camel cousin evolved fluff instead of fat because it was able to linger in an evolutionary slow lane, suggest newly sequenced genomes
Archaeologists unearthed the missing head of one of the two sphinxes found guarding the entrance of an ancient tomb in Greece's northeast, as the diggers made their way into the monument's inner chambers, the culture ministry said on Tuesday.
In what the medical community is calling an incredible breakthrough, a Polish man who was left a quadriplegic after a stabbing, can walk again. The miraculous procedure involved doctors taking cells from his nose and implanting them into his spinal cord.
In a new book, San Francisco-based photographer Susan Middleton captures the curious gestures and expressions of marine invertebrates
Lab at the University of Texas at San Antonio gets Pentagon funding to see if brain waves can direct drone movement
After a severe brain injury, some people remain in a vegetative or minimally conscious state, unable to speak or move intentionally, and apparently unaware of the world around them. But in recent years, neuroscientists have found signs that some of these patients may still be conscious, at least to a degree. Now researchers have used a branch of mathematics called graph theory to search for neural signatures of consciousness.
Few parasitoids are more bizarre or disturbing than the wasps of the genus Glyptapanteles, whose females inject their eggs into living caterpillars. Once inside, the larvae mature, feeding on the caterpillar’s body fluids before gnawing through its skin en masse and emerging into the light of day. And despite the trauma, not only does the caterpillar survive---initially at least---but the larvae proceed to mind-control it, turning their host into a bodyguard that protects them as they spin their cocoons and finish maturing. Then, finally, the caterpillar starves to death, but only after the tiny wasps emerge from their cocoons and fly away.
From their new book A History of Life in 100 Fossils, Paul Taylor and Aaron O'Dea share the story of 10 incredible fossils
We love origin stories. When we see successful groups of animals and plants, we wonder where they came …
First research of its kind shows that tasers could impair a person's memory and thought process