Navigation Links
Age dramatically delays recovery of the sense of taste
Date:4/21/2010

Age dramatically delays the time if takes to recover the sense of taste following a significant nerve injury, Medical College of Georgia researchers said.

When old rats received nerve injuries similar to ones that can occur in ear or dental surgery, their taste buds took essentially twice as long to recover function as their younger counterparts, Dr. Lynnette McCluskey, neuroscientist in the MCG Schools of Graduate Studies and Medicine reported during the Association for Chemoreception Sciences annual meeting April 21-25.

"This is probably something that has a huge quality-of-life impact," said McCluskey, who uses taste buds to study regeneration of sensory nerves that enable touch, vision and hearing as well as taste. Similar studies have shown that age only slightly delays recovery time for neurons that enable movement.

"We did not expect that much of a difference based on the literature for motor neurons so these changes are way more severe than anybody predicted," McCluskey said. "Now we need to find out why before we can start to address ways to improve it."

In younger rats, injury to the chorda tympani nerve, which innervates the front of the tongue, typically prompts an infusion of immune cells called neutrophils to the injury site as well as surrounding tissue. Short-term, the neutrophils, which are like a front-line demolition crew pulverizing tissue for removal, can actually hinder the function of nearby nerves. But soon a similar number of white blood cells called macrophages move in to call off the neutrophils and start cleaning things up. Within 45 days, the witherd taste bud is regenerated, the nerve has recovered and taste is intact. "The nerve grows back, stimulates those cells to regenerate and it hooks up perfectly," McCluskey said.

But older rats experience a much bigger invasion of neutrophils although McCluskey notes it doesn't seem to impact nearby nerve function as with younger rats. "That was better than we expected," she said. They also have proportionately fewer subsequent macrophages moving in which she suspects may be part of the reason for the significantly delayed recovery.

In a paper published this month in Neuroscience, she and co-authors suggest that a balanced response between neutrophils and macrophages enhance recovery. In adult rats, they documented the usual, rapid neutrophil response at the immediate site of a taste system injury and in nearby tissue. When they blocked the neutrophil response, nearby nerve function was unaffected and when they increased neutrophils, it decreased function at least initially in injured and nearby uninjured nerves.

"It's a really tightly controlled interplay between these populations of neutrophils and macrophages. If you mess with it, you are going to change nerve function," McCluskey said. "Ultimately we have to look upstream at some of the adhesion molecules that get upregulated and tell neutrophils to come in."

She knows neutrophils are bad for nerve function when they are present but wants to determine if they have some lasting impact as well, particularly when there are a lot of them. She also wants to know why they are not nearly as mobile in the older rats.

Most old rats eventually recovered their sense of taste but not until at least 85 days after injury. Interestingly taste buds and nerves were present much earlier but apparently not functioning. "That was the really surprising part," McCluskey said. "We don't know if the nerve is completely normal in terms of morphology but it's there." The problem may be that the nerve and taste bud are slower to reconnect, so one of her follow-up studies will be looking at affected nerves as well as well as the form and function of axons, or arms, nerves use to reach out to another cell.

Several studies indicate that taste perception declines with age, even though taste bud numbers hold fairly steady. "People say things don't taste like they used to; they start putting on more salt," McCluskey said. Complicating factors may be a decreased sense of smell and medications that can alter taste.


'/>"/>

Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
Source:Eurekalert  

Related biology news :

1. New drug design technique could dramatically speed discovery process
2. Genetic key discovered to dramatically increase yields and improve taste of hybrid tomato plants
3. Single gene dramatically boosts yield, sweetness in tomato hybrids, CSHL-Israeli study finds
4. CSHL-led team discovers rare mutation dramatically increasing schizophrenia risk
5. Einstein and Pitt researchers develop new TB test that will dramatically cut diagnosis time
6. Duke software dramatically speeds enzyme design
7. Hoarding rainwater could dramatically expand range of dengue-fever mosquito
8. World fertilizer prices drop dramatically after soaring to all-time highs
9. New UGA biomass technology dramatically increases ethanol yield from grasses and yard waste
10. Bangladesh to dramatically expand technology that doubles efficiency of urea fertilizer use
11. New technique could dramatically lower costs of DNA sequencing
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Age dramatically delays recovery of the sense of taste
(Date:6/15/2016)... 2016 Transparency Market Research ... Market by Application Market - Global Industry Analysis Size Share ... the report, the  global gesture recognition market  was ... is estimated to grow at a CAGR of ... Increasing application of gesture recognition technology ...
(Date:6/2/2016)... , June 2, 2016 The ... has awarded the 44 million US Dollar project, for ... Embossed Vehicle Plates including Personalization, Enrolment, and IT Infrastructure ... leader in the production and implementation of Identity Management Solutions. ... January, however Decatur was selected for ...
(Date:5/20/2016)... MINNEAPOLIS , May 20, 2016  VoiceIt ... technology partnership with VoicePass. By working ... user experience.  Because VoiceIt and VoicePass take slightly ... two engines increases both security and usability. ... expressed excitement about this new partnership. ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... CA (PRWEB) , ... June 27, 2016 , ... ... for clinical trials, announced today the Clinical Reach Virtual Patient Encounter CONSULT ... care circle with the physician and clinical trial team. , Using the CONSULT module, ...
(Date:6/27/2016)... June 27, 2016   Ginkgo Bioworks , a ... engineering, was today awarded as one of the ... the world,s most innovative companies. Ginkgo Bioworks is ... the real world in the nutrition, health and ... directly with customers including Fortune 500 companies to ...
(Date:6/24/2016)... ... June 24, 2016 , ... Researchers at the Universita Politecnica delle Marche ... with peritoneal or pleural mesothelioma. Their findings are the subject of a new article ... Diagnostic biomarkers are signposts in the blood, lung fluid or tissue of mesothelioma patients ...
(Date:6/23/2016)... June 23, 2016 /PRNewswire/ - FACIT has announced ... biotechnology company, Propellon Therapeutics Inc. ("Propellon" ... commercialization of a portfolio of first-in-class WDR5 inhibitors ... such as WDR5 represent an exciting class of ... precision medicine for cancer patients. Substantial advances have ...
Breaking Biology Technology: