One of the holy grails of local anesthesia is the ability to achieve a long-lasting nerve block that eliminates pain sensation while not affecting motor function. Now, researchers at Children's Hospital Boston have discovered an anesthetic approach that seems to do just that.
If it proves to work in humans as well as it did in rats, it could be useful in a variety of medical applications, providing, for example, a local anesthetic for childbirth that would block pain without interfering with the mother's ability to push, or for musculoskeletal disorders in which it is important to maintain mobility.
The discovery was reported in the online Early Edition of the Proceedings of the National Academy of Sciences during the week of February 1.
The researchers, led by Daniel Kohane, MD, PhD, of the Division of Critical Care Medicine at Children's, originally sought only to find an agent that would prolong the anesthetics' effects. They focused on surfactants, a subclass of so-called "chemical permeability enhancers" that enable drugs to spread more easily throughout a tissue.
In testing three kinds of surfactant along with the anesthetics QX-314 and QX-222 (both derivatives of lidocaine), they found that this approach did prolong the sensory block in rats' sciatic nerves, for up to 7 hours or more depending on the surfactant, but didn't prolong motor impairment; in some cases the motor block was absent or of very short duration. In the rats, this meant they were able to tolerate having their paws on a hot plate for long periods, yet still able to balance and bear weight on their legs.
"This was a surprise finding," says Kohane, who also directs the Laboratory for Biomaterials and Drug Delivery (LBDD) at Children's. "What we've discovered really is a new approach; the question now is to figure out the mechanism by which it works and look at the effects of other chemical permeability enhancers."
Kohane speculates that surfactant made the anesthetic better able to penetrate sensory nerves, which have little or none of the fatty coating known as myelin, whereas in motor neurons, which have abundant myelin, the active drug gets trapped in the myelin, never entering the nerve itself.
The lab's next steps will be to explore the effects of different permeability enhancers and examine their safety, since at high doses the drug combination could potentially be toxic to the nerves. The eventual plan is to test the approach in larger animals.
A parallel approach to achieving a pain-specific nerve block was proposed in 2007 by Clifford Woolf, MD, PhD, recently appointed director of the Children's Hospital Boston Program in Neurobiology. Woolf's team combined QXT-314 with capsaicin, which opens cellular gates that are only present in sensory neurons, and achieved pain-specific blocks in rats lasting 2 hours or more.
The new study was funded by the National Institutes of General Medical Sciences. Itay Sagie, a research associate at the LBDD was the paper's first author. For licensing information, see: www.childrensinnovations.org/SearchDetails.aspx?id=1679.
Citation: Sagie I and Kohane D. Prolonged sensory-selective nerve blockade. PNAS online early edition, week of February 1, 2010.
Children's Hospital Boston is home to the world's largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults since 1869. More than 500 scientists, including eight members of the National Academy of Sciences, 13 members of the Institute of Medicine and 12 members of the Howard Hughes Medical Institute comprise Children's research community. Founded as a 20-bed hospital for children, Children's Hospital Boston today is a 396-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children's also is the primary pediatric teaching affiliate of Harvard Medical School. For more information about the hospital and its research visit: www.childrenshospital.org/newsroom.
Erin McColgan | EurekAlert!
Routing gene therapy directly into the brain
07.12.2017 | Boston Children's Hospital
New Hope for Cancer Therapies: Targeted Monitoring may help Improve Tumor Treatment
01.12.2017 | Berliner Institut für Gesundheitsforschung / Berlin Institute of Health (BIH)
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...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."
Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...
08.12.2017 | Event News
07.12.2017 | Event News
05.12.2017 | Event News
08.12.2017 | Life Sciences
08.12.2017 | Information Technology
08.12.2017 | Information Technology