when speaking of pain in all its excruciating forms and with all the fear inducing memories associated with some forms of pain, i find it odd that pain sensation begins with the least specialized of all receptors; a bare nerve ending. something i think we all knew is that some pain receptors also respond to acids and heat as is evident when we bite into a jalapeno. the stinging sensation which is derived from jalapenos and other spicy peppers is due to a chemical found in jalapenos themselves called capsaicin. another odd quirk i encountered about capsaicin is that when you have an itch that originated from touching a certain kind of plant you can use the same chemical that caused burning and stinging to ALLEVIATE the sensation! rubbing the skin with capsaicin relieves the itch that cowhage causes, but it has little effect on the itch that histamine causes. (cowhage is a tropical plant with barbed hairs that when touched produces an itching sensation) Yet another use for capsaicin other than to cause a burning sensation when you eat it is to relieve pain. a powerful burning sensation is causes by capsaicin by releasing substance P. however, in the book it states that it releases substance P faster than neurons can re synthesize it, leaving the cells less able to send pain messages. in addition, high doses of capsaicin damage pain receptors. so we can plainly deduce that when Capsaicin is rubbed onto a sore shoulder, or an arthritic joint it produces a temporary burning sensation followed by a longer period of decreased pain. if anything i said causes confusion i'll provide a video shortly after this blog that really helped me understand this concept more in depth: