"This led to the discovery of peptides--the short chains of amino acids that act as chemical messengers--and peptide receptors. Pert found that emotions trigger the release of peptides, which then travel to receptors throughout the body. She calls peptides the molecules of emotion. "A feeling sparked in your mind will translate as a peptide being released somewhere," says Pert, now a neuropharmacologist at Georgetown University School of Medicine. "Peptides regulate every aspect of your body, from whether you're going to digest your food properly to whether you're going to destroy a tumor cell."
Peptide receptors, which are in the organs, endocrine muscle, and other body tissues, store emotional information received from the peptides. Therefore, emotional memories can be stored not only in the brain, but also in many places in the body. That would explain, for example, why people have "gut feelings" or why memories and emotions sometimes pop up during massage or acupuncture--because emotional memories "live" in the body's tissues, Pert says.
The discovery of peptides and peptide receptors offered, for the first time, tangible evidence of the actual physical exchange between mind and body and the biochemical basis of emotion--and confirmed what Eastern healers have long known intuitively. Also, while peptides and their receptors are located throughout the body, they're concentrated in the places that correspond to the chakras, the seven areas around the spine where, according to Eastern medicine, energy is gathered and then distributed to organs and tissues. "It blew me away when I realized this," Pert says.
When your body is in balance, peptides and receptors are able to do their jobs correctly, but when the body is thrown out of balance by intense emotions, the system works less effectively. For example, nervousness might cause a peptide miscommunication that would result in too much water being held in the intestines, and thus, diarrhea--a direct physical result of an emotional state."(From:
http://www.findarticles.com/p/articles/mi_m0NAH/is_8_35/ai_n15979179)
There is plenty of information out there on peptides and how they are basically the way we experience emotions. This is just one site i found, if you want more information on how they work just type in peptides in google and lots of good information will come up