New target to stop bitter tasting drugs
taste modulation that could be the key to helping drug
manufacturers mask bitter, unwanted tastes that turn many people
off their medicines.
The study, published in Nature journal in Decemebr, identified microscopic channels in our taste buds - termed TRPM5 - as being responsible for different taste perception, which also varied according to different temperatures.
According to researchers in Belgium's Katholieke Universiteit Leuven, the reaction of TRPM5 in our taste buds is much more intense when the temperature of solids or fluids is increased, sending a stronger electrical signal to the brain and resulting in an stronger taste.
Pharmaceutical companies are greatly interested in finding ways to soften the bitterness of many drugs. Recent studies estimate that one third of US adults who have been prescribed drugs to take regularly, report that they are often or very often noncompliant with their treatment. 19 per cent of these stated it was because of unpleasant tasting medicine.
>Flavorx, the only company providing FDA approved flavours that are specifically designed for pharmacists to mix with medicines to mask the bitter taste at the point of dispensing, are experiencing great demand in the marketplace.
The success of Flavorx hinges around the fact that it fills a world-wide gap in the market, as the problem of foul-tasting medication and resultant poor medication compliance are global issues, which have until now been poorly addressed.
Bitter taste inhibitors, that could be incorporated in medicine formulations during the actual manufacturing process, will therefore represent a huge marketing advantage.
So far, the search of bitter inhibitors has focused on the block of bitter taste receptors (membrane proteins in the cells of the taste buds that bind bitter compounds). However, the search for these compounds is very difficult for two reasons.
Firstly, there are a large number of different bitter receptors and it would be very hard to obtain compounds that will efficiently inhibit all off them. Secondly, compounds that would interact with bitter receptors will, most likely, behave themselves as bitter compounds.
Given that TRPM5 channels represent a convergent point in the pathway of transduction of bitter taste to the brain, TRPM5 is now being recognised by pharmaceutical companies as a promising target for the design of bitter taste inhibitors.
According to lead author Dr Karel Talavera and his colleagues, their findings could allow for the modification of the taste channel in order to achieve required tastes.
"Taste perception could be modulated by adding something to the product that could enhance or inhibit the work of the TRPM5 channel, or by changing the temperature of the product," said Dr Talavera.
He added, however, that his team of researchers had little knowledge of the family of chemicals that could be used, but suggested their findings serve as a starting point for further investigation by pharmaceutical companies.
Previous research into taste has revealed that the human tongue has about 10,000 taste buds with five taste sensations: sweet, bitter, and umami, which work with a signal through a G-protein coupled receptor; salty and sour which work with ion channels.
Contrary to popular understanding, taste is not experienced on different parts of the tongue. Though there are small differences in sensation, which can be measured with highly specific instruments, all taste buds, essentially clusters of 50 to 100 cells, can respond to all types of taste.
Taste buds (or lingual papillae) are small structures on the upper surface of the tongue that provide information about the taste of things being placed in the mouth.
