What makes us scratch an itch?

BEIJING — We itch, we scratch, we scratch, we itch, what is the science behind this annoying cycle?
A recent study published in the journal Neuron reveals that a small category of neurons located in an area of the brain called the periaqueductal gray tracks itch-evoked scratching behavior in mice.
Researchers from the Chinese Academy of Sciences studied periaqueductal gray neurons of freely moving mice that were induced to scratch through injections containing histamine, or chloroquine.
Histamine is an organic compound involved in itch perception and chloroquine is a medication used to treat malaria.
The team then studied the itch-induced scratching behavior by observing the activity of a set of neurons that produce a neurotransmitter called tachykinin 1 or Tac1 which produces glutamate and neuropeptides.
Scientists observed that when Tac-1 neurons were eliminated itch-induced scratching also decreased.
Stimulating these neurons, on the other hand, resulted in spontaneous scratching behavior even without using histamine and chloroquine injections.
Scientists participating in the study will continue to investigate which molecules in the Tac1 can be targeted by drugs. This would allow for the development of a drug that could be used to treat patients with chronic itch.