A Novel Invertebrate Model for Pain Research: The Development of Effective 8-methyl-N-vanillyl-6 nonenamide (Capsaicin) Adjuvants to Reduce Initial Pain Signals from TRPV1 Ion Channels Using Hirudo Medicinalis.

Newnham, Caitlin Martin

Capsaicin is the oil found in hot peppers that causes an initial burning sensation and later, numbness. It is used as a pain reliever because of its ability to degenerate the endings of nociceptors (pain neurons). With the reduction of the initial burning sensation, capsaicin is an efficient pain-reliever with few side effects and no known drug interactions. Capsaicin also complexes specifically to TRPV1, a ligand-gated cation channel, that is only found in the cell membrane of nociceptors; thus preventing capsaicin from numbing other types of neurons. To research with capsaicin, an invertebrate model for pain research had to be developed since the only models for pain research were vertebrates. The leeches reacted to capsaicin with frequent, vigorous, whole-body length changes, which was drastically different than the leeches' reaction to saline, an isotonic solution. In saline, leeches had little to no movement. It was discovered through experimentation that an injection of sodium chloride solution preceding a topical application of capsaicin reduces the initial burning. This decrease in reaction was due to sodium chloride denaturing Substance P, the neuropeptide that signals pain. Also, sodium chloride is a contributor to pain neuron ending degeneration. An invertebrate model for pain has been discovered, along with a capsaicin admixture that reduces the initial burning sensation.

CAPSAICIN; ANALGESICS; DRUG side effects; NEURONS; THERAPEUTICS; BIOTECHNOLOGY research

Canadian Young Scientist Journal, 2010, Vol 2010, Issue 1, p27

1913-1925

Academic Journal