What does capsaicin do to your tongue that causes the sensation of pain?

Question

What exactly does it do to your tongue to cause it to burn? Or for that matter if you touch it with your fingers and then you touch your eyes? What is occuring to the nerves?

Answer 1

The last person did a better job of answering than I could, but here's an aside you might find interesting.

I read that birds have no capsaicin receptors and happily eat hot peppers. In the process, they swallow the seeds and then pass them intact. Mammals, however, crush seeds by chewing, and are bothered by the capsaicin. Thus, plants evolved capsaicin as a mechanism to protect their seeds without discouraging birds who help distribute the seeds.

Answer 2

Capsaicin, is a molecule found in the white "ribs" of hot peppers that is the root of our perception of heat from the peppers. It is assumed to be a defense mechanism in a variety of pepper plants. The capsaicin found in hot peppers work by binding to and stimulating capsaicin receptor proteins found in neuronal cells. The fibers of the neuronal cells then carry the stimulus from areas such as the tongue, to the roots of the spinal cord. Capsaicin also allows a deluge of calcium ions to enter the neuron. This is dangerous, because an extended exposure to calcium causes the fibers of the neuron to die.

Answer 3

U gotta swallow it whole, its make out of red hot peppers...