Our lungs can 'taste' bitterness in the air, say scientists

The human lungs can "taste" bitter substances in the air, according to a study that could lead to new types of drugs designed to make it easier for asthma sufferers to breathe.

It is the first time that taste receptors, normally found on the tongue, have been discovered in the involuntary smooth muscle that controls the flow of air into the bronchi, the narrow airways of the lungs.

Scientists said the taste receptors are identical to those designed to detect the presence of bitter compounds in the mouth but, unlike the taste buds on the tongue, the receptors in the lungs do not send nerve impulses to the brain.

The discovery, published in the journal Nature Medicine, was so surprising that the researchers who made it initially thought they had made a mistake. They also discovered that, rather than narrow the tubes of the lungs to protect them against bitter, poisonous gases, stimulating the receptors actually widened the airways.

"Nobody expected that taste receptors, considered to be for the tongue, would be found on the smooth muscle of the bronchi," said Professor Stephen Liggett of the University of Maryland Medical Centre in Baltimore. "When we [stimulated] these cells, we figured that they would constrict the muscle, signaling a person to leave a toxic environment. Instead, they open the airways better than any known drug for treating asthma."

Many poisons made by plants are bitter, so the scientists thought that the receptors must play a role in warning the lungs of a potentially toxic environment. "I initially thought the bitter-tasting receptors in the lungs would prompt a 'fight or flight' response to a noxious inhalant, causing chest tightness and coughing so you leave a toxic environment, but that's not what we found," Professor Liggett said.

"It turns out that the bitter compounds worked the opposite way. They opened the airway more profoundly than any known drug that we have for treatment of asthma or chronic obstructive pulmonary disease," he said.

"New drugs to treat asthma, emphysema or chronic bronchitis are needed. This could replace or enhance what is now in use, and represents a completely new approach."

There is no possibility that the lungs could be subconsciously used to "taste" air, Professor Liggett said. "In the tongue, there is a neural pathway from the taste bud to the brain. There is no such pathway in the lungs. The receptors are on the airway smooth muscle, and signal to the interior of the cell to cause it to relax," he said.

One explanation for their presence is that the taste receptors detect bacterial infections which secrete bitter substances, thereby ensuring that the vital airways are kept open.

Start your day with The Independent, sign up for daily news emails
Voices
There will be a chance to bid for a rare example of the SAS Diary, collated by a former member of the regiment in the aftermath of World War II but only published – in a limited run of just 5,000 – in 2011
charity appealTime is running out to secure your favourite lot as our auction closes at 2pm today
News
people
News
Elton John and David Furnish exchange marriage vows
peopleSinger posts pictures of nuptials throughout the day
News
File: James Woods attends the 52nd New York Film Festival at Walter Reade Theater on September 27, 2014
peopleActor was tweeting in wake of NYPD police shooting
PROMOTED VIDEO
Sport
Martin Skrtel heads in the dramatic equaliser
SPORTLiverpool vs Arsenal match report: Bandaged Martin Skrtel heads home in the 97th-minute
Arts and Entertainment
The Lord of the Rings and The Hobbit director Peter Jackson with his star on the Hollywood Walk of Fame
film
News
people
News
Billie Whitelaw was best known for her close collaboration with playwright Samuel Beckett, here performing in a Beckett Trilogy at The Riverside Studios, Hammersmith
people'Omen' star was best known for stage work with Samuel Beckett
Arts and Entertainment
Mark Wright has won The Apprentice 2014
tvThe Apprentice 2014 final
News
i100
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Manufacturing Manager

£35000 - £38000 per annum: Recruitment Genius: This is a rare opportunity for ...

Recruitment Genius: Conveyancing Fee Earner / Technical Support

£20000 - £30000 per annum: Recruitment Genius: An experienced Fee Earner/Techn...

Recruitment Genius: Receptionist

Negotiable: Recruitment Genius: This law firm is seeking a happy, helpful and ...

The Jenrick Group: Production Supervisor

£26000 - £29000 per annum + Holidays & Pension: The Jenrick Group: Production ...

Day In a Page

Surrounded by high-rise flats is a little house filled with Lebanon’s history - clocks, rifles, frogmen’s uniforms and colonial helmets

Clocks, rifles, swords, frogmen’s uniforms

Surrounded by high-rise flats is a little house filled with Lebanon’s history
Return to Gaza: Four months on, the wounds left by Israel's bombardment have not yet healed

Four months after the bombardment, Gaza’s wounds are yet to heal

Kim Sengupta is reunited with a man whose plight mirrors the suffering of the Palestinian people
Gastric surgery: Is it really the answer to the UK's obesity epidemic?

Is gastric surgery really the answer to the UK's obesity epidemic?

Critics argue that it’s crazy to operate on healthy people just to stop them eating
Homeless Veterans appeal: Christmas charity auction Part 2 - now LIVE

Homeless Veterans appeal: Christmas charity auction

Bid on original art, or trips of a lifetime to Africa or the 'Corrie' set, and help Homeless Veterans
Pantomime rings the changes to welcome autistic theatre-goers

Autism-friendly theatre

Pantomime leads the pack in quest to welcome all
The week Hollywood got scared and had to grow up a bit

The week Hollywood got scared and had to grow up a bit

Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

Panto dames: before and after

From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
Thirties murder mystery novel is surprise runaway Christmas hit

Thirties murder mystery novel is surprise runaway Christmas hit

Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

Anne-Marie Huby: 'Charities deserve the best'

Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
The botanist who hunts for giant trees at Kew Gardens

The man who hunts giants

A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there
The 12 ways of Christmas: Spare a thought for those who will be working to keep others safe during the festive season

The 12 ways of Christmas

We speak to a dozen people who will be working to keep others safe, happy and healthy over the holidays
Birdwatching men have a lot in common with their feathered friends, new study shows

The male exhibits strange behaviour

A new study shows that birdwatching men have a lot in common with their feathered friends...
Diaries of Evelyn Waugh, Virginia Woolf and Noël Coward reveal how they coped with the December blues

Famous diaries: Christmas week in history

Noël Coward parties into the night, Alan Clark bemoans the cost of servants, Evelyn Waugh ponders his drinking…
From noble to narky, the fall of the open letter

From noble to narky, the fall of the open letter

The great tradition of St Paul and Zola reached its nadir with a hungry worker's rant to Russell Brand, says DJ Taylor
A Christmas ghost story by Alison Moore: A prodigal daughter has a breakthrough

A Christmas ghost story by Alison Moore

The story was published earlier this month in 'Poor Souls' Light: Seven Curious Tales'