A dentist’s injection typically causes numbness for several hours. This experience could soon be history. Now, Clifford Woolf, professor at Harvard Medical School and the Massachusetts General Hospital, Boston, USA, and his colleagues have developed a combination of two agents which is able to specifically block pain without producing numbness or motor paralysis.
The substance is composed of a normally inactive derivative of the local anesthetic lidocaine, called QX314, and capsaicin, the pain-producing substance in chili peppers, ScienceDaily said. Capsaicin works by opening channels present only in pain fibers to allow the QX314 only into these cells, where it blocks their function, Woolf explained in the keynote lecture “Using Pain to Block Pain“ at the international conference “Development and function of somatosensation and pain“ of the Max Delbruck Center for Molecular Medicine (MDC) Berlin-Buch, Germany. “This is the first example of using the body’s own cellular channels as a drug delivery system, targeting treatment only at pain fibers,“ he pointed out.
Local anesthetics are pain killers which are used during operations whereby patients remain alert during the procedure and thus, do not require general anesthesia.
“These common analgesics, including lidocaine, affect, however all neurons in the treated area,“ Woolf said. As a result, not only are pain receptors blocked but also touch receptors, producing numbness. Neurons, controlling muscles, are silenced as well, producing a temporary paralysis.
In order to specifically block pain receptors and leave touch sensors and motor function unharmed, the scientists used a normally inactive positively charged form of the local anaesthetic lidocaine called QX314.
This particular type of lidocaine is special in that it is not able to pass through the cell membrane of neurons because it is charged. Since local anesthetics only operate inside neurons, an injection of QX314 alone is ineffective, unlike lidocaine which passes easily through the membrane of all cells and therefore blocks all neurons.
As QX314 only enters pain neurons and, thereby, acts exclusively as a pain killer, the researchers combined it with capsaicin. Capsaicin binds a membrane receptor which is only present in the membrane of neurons responsible for pain perception.
Thus, the chili pepper substance opens channels, enabling QX314 to get into the cell and then block the pain receptors. Using rats, the scientists could show that, when applied to the animals’ hind paws, the combination of QX314 and capsaicin exclusively blocks pain receptors. While completely blocking the response to painful stimuli, the animals could, nevertheless, move normally and were responsive to touch.
There is, however, one disadvantage of this current strategy, said Woolf. Capsaicin activates the sensors for pain and heat. “Thus, people’s mouths seem to burn when eating very spicy food,“ he said.

Italian researchers have some advice for those with high blood pressure: Breathe slowly. Turn on some quiet, rhythmic music. And watch your high blood pressure take a little tumble.
According to HealthDay, the researchers base their conclusions on a small new study. But they aren’t suggesting anyone turn to breathing exercises and music instead of medicine.
Still, “easy and enjoyable daily music listening combined with slow abdominal breathing may help people naturally lower their blood pressure,“ said Dr. Pietro A. Modesti, a professor of internal medicine at the University of Florence.
The study authors also found that other non-drug ’interventions’--including restriction of salt intake--had about the same effect.
“Further studies are needed to confirm the effect in the long term,“ Modesti said.
Researchers have previously found that relaxation can relieve people’s cardiovascular symptoms. But the researchers behind the new study discovered that relaxation significantly affected blood pressure only if it was combined with quiet music.

Students of Isfahan University of Technology have built an economy car that can travel 500 kilometers on one liter of gas for the first time in the Middle East.
According to IRNA, the student team will compete in Shell Eco-Marathon in France as the only participant from the Middle East.
The event targets building cars that have the least energy consumption level and is sponsored by the oil giant Shell.
In this year’s competition, 24 countries, which are mostly European, will be vying.
The length of this car is 2.9 meters, its width is one meter and height 90 centimeters.
Among the features of the car are the low rolling resistance of tires and a continuously variable transmission (CVT ).
The flexibility of a CVT allows the driving shaft to maintain a constant angular velocity over a range of output velocities.
This can provide better fuel economy than other transmissions by enabling the engine to run at its most efficient revolution per minute (RPM) for a range of speeds.