Chillis won't leave you numb
Scientists may have found the Holy Grail of pain killers
The Holy Grail in pain science is to eliminate pathologic pain without impairing thinking, alertness, coordination or other vital functions of the nervous system.
Hate being left numb and drooling after visiting the dentist? A local anaesthetic that targets just pain-sensing neurons could make these trips less traumatic.
A chemical from chilli peppers may be able to kill pain without affecting touch or movement. This might in theory mean a woman in labour could have an epidural without losing the ability to move her legs, or the sensation of her baby being born.
Conventional local anaesthetics affect all nerve cells. But researchers at Harvard Medical School say that with capsaicin, the chilli chemical, they can target just pain receptors.
Local anaesthetics such as lignocaine work by diffusing into all neurons and blocking channels that transport sodium ions across cell membranes - leaving the person in the dentist's chair pain-free but numb.
Clifford Woolf and his colleagues at Harvard Medical School have now discovered a way of blocking just the pain neurons using capsaicin - the active ingredient in chilli peppers - along with a version of lignocaine that can't diffuse through cell membranes unassisted.
Capsaicin activates the TRPV1 receptor on pain neurons. This in turn opens up a channel on the neurons' membrane, allowing the lignocaine to pass though. The drug then gets to work blocking the sodium channels. In tests on rats the drug combination completely blocked pain without affecting motor function or other senses.
However, some experts believe it might be difficult to inject it safely.
Numbness is actually a side-effect of the pain-killing properties of local anaesthetics - caused when the drug blocks signals not only from the nerve endings which cause pain, but other nerve endings which simply detect the sensation of touch.
And when anaesthetic "blocks" are injected into the spine, they can interfere with other nerves, causing temporary paralysis -- such as that felt in the lower limbs after an epidural injection.
Woolf's team is testing other chemicals that can activate the TRPV1 receptor, since people may not like the initial pain of a dose of chilli pepper. Tests on volunteers are expected within two years.
The possibilities are intriguing. The anaesthetic based on chilli peppers could allow patients to undergo operations while fully conscious. Woolf and Bean have even postulated that they could adapt their findings to produce a compound to deaden itches.
Science Forum is written and compiled by Rashida Ahmad.
Constellation cancer reveals five-planet system
Astronomers have spotted a record-setting fifth planet orbiting the sunlike star 55 Cancri, 41 light years away in the constellation Cancer. Weighing about 46 Earth masses, it was discovered in the estimated habitable zone around the star where water might remain liquid, according to last month's The Astrophysical Journal. Although its size implies it is a gas planet incapable of supporting liquid water, the finding raises the possibility that earthlike planets might be discovered around it. One of the first stars found with extrasolar planets, the 55 Cancri system resembles a jumbo version of our own solar system. Before this discovery, researchers knew of only one other four-planet system and several three-planet systems.
Smiling cars and friendly computers
A forthcoming study from the Journal of Consumer Research looks at how consumers anthropomorphise products, endowing a car or a pair of shoes with human characteristics or personalities. The North American study finds that people are more likely to attribute human traits to an inanimate object if it fits their expectation of relevant human qualities, and are more likely to positively evaluate an anthropomorphised product. For example, they found people more likely to buy a "family" of products if they are differently sized, representing "parents" and "kids." They also found identical looking objects presented as "good" twins were better liked than the same products presented as "evil" twins!
Faster than the speed of light
It's a speed limit that is supposed to be impossible to break. Yet two German physicists now claim to have propelled photons faster than the light speed. This would directly violate a key tenet of Einstein's special theory of relativity, which states that nothing can exceed the speed of light. The two scientists, of the University of Koblenz, have been studying a quantum phenomenon called photon tunnelling, where a particle slips across an apparently un-crossable barrier. They say they have tunnelled photons "instantaneously" across barriers from a few millimetres to a metre thick. Their conclusion is that the photons traverse the barrier much faster than the speed of light.
Chocolate from beer
Chocolate was first produced by the ancients as a by-product of beer, suggests a new archaeological study. And evidence from drinking vessels left by the Mesoamericans who developed chocolate suggests that cacao was first used 500 years earlier than thought. Mesoamericans -- who flourished in central America before Spanish colonisation -- developed chocolate as a by-product of fermenting cacao fruit to make a beer-like drink called chichi, still brewed by South American tribal people. Developing a taste for the chocolate, unfermented cacao drinks became a central element of Mesoamerican cultures including Aztec, from whom Europeans learned of chocolate in the 16th century.
Chimps dig up clues to human past?
Chimpanzees in Tanzania are found to use sticks to dig for edible roots, tubers and bulbs, scientists at the University of California, San Diego, report. The findings are important as they show that stick tools are not a uniquely human adaptation, and they provide insights into the role of a dietary shift in human evolution. Changes in the teeth and jaws of the first hominids provide evidence of foods requiring heavy chewing some 3 to 4 million years ago. Meat, nuts and "roots, bulbs and tubers" have all been posited as enabling these early hominids to succeed in new environments. But sticks decay rapidly whereas stone points are preserved, leading many researchers to focus on meat and hunting. The modern chimp, our closest living relative, is now providing clues to an alternative theory.
Harvesting the power of the heart
Implanted pacemakers and defibrillators have to be replaced when their built-in power sources run low -- normally every 7 to 10 years -- and surgery carries risk for patients. So researchers at Stanford University, California, say it would be better for the devices to harvest their own power from the human body. The team has come up with a number of designs which generate power by virtue of being attached to the outside of the heart. This causes, for example, a magnet to move through a coil in a way that generates current. The scientists say this could make implantable devices self-powering, or at the very least, increase the periods between replacements.