Cilia Affect Sense of Touch, Researchers Find

Cilia look like microscopic tails that are found all over the surface of all of the cells in the body. Their job is to act like very tiny flippers and help the cells navigate around the body. But now researchers from Johns Hopkins have discovered that they have another important job to perform. They help form our sense of touch.

The researchers found, that in humans as well as genetically engineered mice who do not have working cilia. will respond more slowly to physical stimulation than someone who does The researchers hope that the results of the study will help lead to a better understanding of diseases that are already known to be associated with non working cilia such as Bardet-Biedl syndrome (BBS) and polycystic kidney disease (PKD).

The known roles for the cilia are becoming more numerous with the researchers discovering that they are involved in many other body functions, including three of our five senses: vision, hearing, and smell. They decided to test one of the two remaining senses, either taste to touch. They picked touch.

In the study, they conducted tests on normal mice and engineered mice who had defective cilia known as Bbs -.The first thing they did was to test for heat sensitivity by putting the mice' tails in warm water and seeing how long it took for the mice to flick their tails. The second thing was to test mechanical force by applying increasing pressure, but not enough to cause pain to the animal, on the hind feet of the mice and measured how long it took for them to move..

The results in both tests were that the response time of the Bbs- mice was longer. They had a higher threshold for the pain. They tested the mice on a spinning rotor and their coordination was normal, so that ruled out motor problems as a cause of the slower responses.

They also repeatedly dunked one hind paw in hot water for an hour and them they measured the nerve activity at the base of the spinal cord, the place that is the junction between the leg and the brain. The regular mice showed clear spinal nerve activity, but the Bbs- mice did not, which means that the sensory information does not reach the brain.