The Hyperacusis Network Message Board
Sign up Latest Topics
 
 
 


Note: This topic is locked. No new replies will be accepted.


Reply
  Author   Comment  
DanMalcore

Avatar / Picture

Dan
Registered:
Posts: 1,411
Reply with quote  #1 
Unlocking the mystery of misophonia remains a puzzle.  In my view, we have a lot to learn about how special cells in our body (some specific to each person) react to many things  -   some of which are smells and, I don't think it is a big stretch to say...sounds too.  For example, I have heard from individuals who react severely to certain sounds (vomit or become paralyzed until the sound stops or they are removed from the sound).  This is another interesting news alert sent to the network by the NIDCD (National Institute on Deafness and Other Communicative Disorders).



Irritating Smells Alert Special Cells, NIH-Funded Study Finds

Embargoed for Release
Tuesday, March 4, 2008
12:01 a.m. EST

Contact:
Linda Joy
(301) 496-7243
ljoy@mail.nih.gov

If you cook, you know. Chop an onion and you risk crying over your cutting board as a burning sensation overwhelms your eyes and nose. Scientists do not know why certain chemical odors, like onion, ammonia and paint thinner, are so highly irritating, but new research in mice has uncovered an unexpected role for specific nasal cavity cells. Researchers funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, describe this work in the March issue of the Journal of Neurophysiology, now available online.

Weihong Lin, Ph.D., of the University of Colorado Denver School of Medicine and University of Maryland, Baltimore County, led the study which discovered that a particular cell, abundant near the entry of many animal noses, plays a crucial and previously unknown role in transmitting irritating and potentially dangerous odors. Dr. Lin and colleagues from both universities plus the Mount Sinai School of Medicine identified the role of this solitary chemosensory cell in transmitting irritating chemical odors in the noses of mice.

Scientists have found similar solitary chemosensory cells in the nasal cavities, airways and gastrointestinal tracts of many mammals as well as fish, frogs and alligators; they think it is likely that they are also present in humans, explains Thomas Finger, Ph.D., one of the senior co-authors at the University of Colorado Denver.

Prior to this work, scientists who study smell and taste thought that irritating odors directly stimulated the trigeminal nerve, which senses touch, temperature and pain  throughout the head region, including the delicate membranes that line the inside of the nose. The research team, under the guidance of Diego Restrepo, Ph.D., found that solitary chemosensory cells scattered in the epithelium inside the front of the nose respond to high levels of irritating odors and relay signals to trigeminal nerve fibers.

“This elegant research corrects an erroneous assumption about how irritating odors are perceived and expands our understanding of olfaction,” says James F. Battey, M.D., Ph.D., director of NIDCD. “With further investigation, it also might lead to a better understanding of why some people are exceptionally sensitive to irritating odors.”

Solitary chemosensory cells on the surface of the nasal cavity are in close contact with trigeminal nerve fibers which end just below the surface. Earlier research revealed that these cells contain bitter taste receptors and that bitter substances applied to the surface of the nasal cavity trigger a trigeminal nerve response.

Intrigued, Drs. Restrepo and Finger decided to explore whether solitary chemosensory cells respond to irritating odors. Using nasal tissue from mice, the scientists measured a variety of changes in solitary chemosensory cells as they exposed the cells to low and high levels of several irritating, volatile chemical odors.

Among their observations were changes in electrical activity in the cells—which indicates a response to an outside stimulus—and changes in intracellular calcium ion concentration—which indicates signaling to other cells. Their measurements demonstrated that the solitary chemosensory cells responded to the odors and relayed sensory information to trigeminal nerve fibers.

Once stimulated, the trigeminal nerve will convey pain and burning sensations and can trigger protective reflexes such as gagging and coughing. The architecture of nasal tissue with solitary chemosensory cells on the surface and trigeminal nerve fibers just below allows the nose to detect a greater number of irritating odors, the scientists explain.

Fortunately, the threshold for triggering a response is high, so exposure to a small amount of an irritating chemical, as might naturally emanate from some kinds of fresh fruit, will not bring on gagging and coughing. For example, lemons contain the volatile chemicals citral and geraniol but at levels too low to trigger a trigeminal response. Only high, potentially dangerous levels of odors will trigger the protective gagging-and-coughing response.

The researchers point out that their findings provide an example of the Law of Specific Nerve Energies, conceived by Johannes Peter Muller in 1826. Muller said that the way we perceive a stimulus depends on the nerve or sensory system that conveys it rather than the physical nature of the stimulus itself. In the case of irritating odors, we perceive them as irritating because they are transmitted via the trigeminal nerve, leading the brain to interpret the message as pain rather than as a smell.

The researchers say their findings raise new questions about how irritating odors are detected. They say more research is needed to explore whether solitary chemosensory cells are programmed to recognize specific irritants, which receptors are involved, and what steps a solitary chemosensory cell uses to convert a chemical stimulus to a signal it relays to the trigeminal nerve.

The NIDCD supports and conducts research and research training on the normal and disordered processes of hearing, balance, smell, taste, voice, speech and language and provides health information, based upon scientific discovery, to the public. For more information about NIDCD programs, see the Web site at http://www.nidcd.nih.gov.

NIH—the nation’s medical research agency—includes 27 institutes and centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.




__________________
"Yesterday is ashes, tomorrow is wood, only today does the fire burn brightly"
0


Registered:
Posts: N/A
Reply with quote  #2 
Then this article might lead one to believe that sound sensitivity is a PHYSIOLOGICAL PROCESS, as I have been Shouting for about ten years now, as opposed to some kind of psychological-emotional reaction.............

This is something I have stated based on hundreds of first hand interviews with people who suffer these specific symptoms related to specific sounds.

I have been able to hold true to their stories despite quite a bit of skepticism and criticism.

Misophonia implies a choice-factor.  I do not 'choose' to cry when I peel an onion as the article points out.

One day, I believe that the term misophonia may finds its own place in the world of auditory science, but people with the distinctly different symptoms of 4S will also be recognized and responded to in an efficacious manner....whether that would include any inclusion of sound therapy remains to be determined.

It may be a chemical transmitter shifting agent could do the trick and persist in its effect (like a cure).

I hope so.

Dr. J
0
DanMalcore

Avatar / Picture

Dan
Registered:
Posts: 1,411
Reply with quote  #3 
Quote:
Then this article might lead one to believe that sound sensitivity is a PHYSIOLOGICAL PROCESS


I don't agree Marsha.  This article addresses the topic of: We don't know what we don't know.  Misophonia is well defined by Dr. Jastreboff and is the proper term for dislike of sound or specific sounds.  I see nothing that says it implies a choice factor.  4S is a term which needs to expire.

Dan


__________________
"Yesterday is ashes, tomorrow is wood, only today does the fire burn brightly"
0
LynnMcLaren

Registered:
Posts: 7,990
Reply with quote  #4 
Interesting... ((( Smiles )))

Special cells....
Later I'm going to look up the law of specific nerve energies as I've never heard of that before.... 
And it has something to do with the gastrointestinal tracts as well....
I got to look that up and see what Johannes Muller wrote about it... 
It must be interesting reading indeed......

__________________
Take Care

Lynn
0
LynnMcLaren

Registered:
Posts: 7,990
Reply with quote  #5 
That is interesting....(((( Smiles ))))

The amazing intelligence inside ones body..
It never cease's to amaze me and when it works...
It works so well.. And when something goes wrong...
We take notice and never question it when it does works so well..
Only when it doesn't for some reason, we think about it alot...
I've never read Mullers writings before...
But as it's late... Bed time for me....
I'm going to check it out more later.....
Night Night...      


Müller's statement of the law, from Handbuch der Physiologie des Menschen für Vorlesungen, 2nd Ed., translated by Edwin Clarke and Charles Donald O'Malley:

The same cause, such as electricity, can simultaneously affect all sensory organs, since they are all sensitive to it; and yet, every sensory nerve reacts to it differently; one nerve perceives it as light, another hears its sound, another one smells it; another tastes the electricity, and another one feels it as pain and shock. One nerve perceives a luminous picture through mechanical irritation, another one hears it as buzzing, another one senses it as pain. . . He who feels compelled to consider the consequences of these facts cannot but realize that the specific sensibility of nerves for certain impressions is not enough, since all nerves are sensitive to the same cause but react to the same cause in different ways. . . (S)ensation is not the conduction of a quality or state of external bodies to consciousness, but the conduction of a quality or state of our nerves to consciousness, excited by an external cause.


__________________
Take Care

Lynn
0
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.



This message board is for informational purposes only. It is not intended to substitute for any medical advice. MANDATORY BOARD ETIQUETTE: 1. No personal attacks. 2. No profanity or use of inappropriate usernames. 3. No self solicitation of goods or services. 4 No discriminatory remarks based on race, gender, or religion. 5. Prohibitive postings include the following: discussing or suggesting the intent to end one's life, moderating or actions made by the moderators, and/or revealing personal information (full names, address, phone number). Rule infraction may result in either a warning or ban, depending on the severity. Kindness matters.