A common thread: No pain, no smell

Mar 25, 2011 by Deborah Braconnier report

(PhysOrg.com) -- In a recent study published in Nature by Jan Weiss and Frank Zufall of the University of Saarland, School of Medicine, a connection has been made between the inability to feel pain and anosmia - the inability to smell. The connection discovered involves the sodium ion channel called Nav1.7.

The researchers examined three people with a rare condition known as congenital analgesia. This condition leaves patients with the inability to feel . The researchers were already aware that the cause of this disorder is a lack of the sodium ion channel Nav1.7 in the dorsal root ganglion and ganglia of the , but they wanted to learn if patients also experienced any other sensory issues.

The three participants were able to see and hear as well as any other healthy individual, but when it came to the sense of smell, they were unable to distinguish the odors of vinegar, orange, mint, perfume, or coffee. The study had scents so strong that others with normal senses of smell were unable to tolerate it.

To determine if it was in fact the same responsible for the sense of smell, Weiss and his team examined tissue samples from the nose and olfactory system of normal people and this revealed the Nav1.7 channels in the neuron’s cell membranes.

Weiss bred a group of mice lacking the Nav1.7 ion in their olfactory neurons and witnessed the same results. Mice generally search out and react to certain scents, but these mice showed no interest. When a mother mouse was separated from her young, she was unable to locate and gather them together.

The connection between Nav1.7 and sensory systems also shows earlier evidence that taste may also be included. The idea that our main senses are in some way linked to pain can now be better explored.

Other implications of this study could result in the ability to eventually treat people who have lost their . This study could also have implications on the required side effects listings on many popular painkillers. These particular sodium ion channels are what are targeted by many painkillers, and a new side effect of anosmia may need to be listed.

Explore further: Stem cells faulty in Duchenne muscular dystrophy

More information: Loss-of-function mutations in sodium channel Nav1.7 cause anosmia, Nature (2011) doi:10.1038/nature09975 , http://www.nature.com/nature/journal/vaop/ncurrent/full/nature09975.html

Related Stories

Study: Why cold is such a pain

Jun 14, 2007

German scientists have identified a key molecule that helps animals feel pain associated with low temperatures.

Common mechanism underlies many diseases of excitability

Dec 28, 2009

Inherited mutations in voltage-gated sodium channels (Navs) are associated with many different human diseases, including genetic forms of epilepsy and chronic pain. Theodore Cummins and colleagues, at Indiana University School ...

Olfactory bulb size may change as sense of smell changes

Jun 16, 2008

The olfactory bulb in the brain appears to change in size in a way that corresponds to individual alterations in sense of smell, according to a report in the June issue of Archives of Otolaryngology–Head & Neck Surgery.

Recommended for you

Stem cells faulty in Duchenne muscular dystrophy

23 hours ago

Like human patients, mice with a form of Duchenne muscular dystrophy undergo progressive muscle degeneration and accumulate connective tissue as they age. Now, researchers at the Stanford University School of Medicine have ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.