Taste cells in weird parts of your body

Everyone knows that taste and smell are intimately related, but what you might not know is that you have actual 'taste' cells in your nose (the nasal epithelium to be exact). 

Don't drink this way (source).

But before you go try to drink through your nose, read on, the story gets weirder.  These 'taste' cells express the T2R receptor which senses 'bitterness'. However, if you sniff some 'bitter' molecules into your nose, you won't feel like you are tasting bitterness because these cells don't go to the official 'taste' part of the brain.  In fact, they do something even cooler.  I'll let a previously-blogged-about author, Dr. Finger, explain:

"Since the SCCs synapse onto polymodal pain fibers in the trigeminal nerve, activation of the SCCs by bitter ligands evokes trigeminally mediated reflex changes in respiration." (Finger and Kinnamon 2011)

The SCCs are the 'solitary chemosensory cells' which are the 'taste' cells in the nose that I was talking about. And basically what Dr. Finger is saying is that when stimulated, these cells cause you pain and change the rate at which you breath. This is probably because it is not evolutionarily healthy to have something bitter up your nose and you might not want to breath it in deeply. Might be poison. 

If taste cells in the nose isn't weird enough, here is a diagram of all the other strange places in your body where 'taste' cells have been found:


Taste cells in the body Figure 2 (Finger and Kinnamon 2011)

So why do you need taste cells in your stomach? Well these cells don't send signals to the taste center of the brain either, but they do release ghrelin, which is an appetite-inducting peptide.  Since the taste receptors in the stomach have T1R receptors which respond to sweetness and amino acids (glutamate), this could be a signal saying 'yum, this is good stuff, keep eating'.

But why would there be taste cells in the bile duct? 
The authors of this review paper don't have that answer either:

"The composition of fluid in the bile ducts is dictated by secretions of the liver, pancreas, and gall bladder, so why is it necessary to diligently monitor the composition of biliary fluids and they move from gall bladder to intestines?" (Finger and Kinnamon 2011)

The moral of the story: Even though cells in weird parts of the body are shaped like taste cells and have taste receptors on them, they don't necessarily make you feel the feeling of taste, but they might serve other important survival functions.

© TheCellularScale


Finger TE, & Kinnamon SC (2011). Taste isn't just for taste buds anymore. F1000 biology reports, 3 PMID: 21941599