A central neural circuit for itch sensation

Although itch sensation is an important protective mechanism for animals, chronic itch remains a challenging clinical problem. Itch processing has been studied extensively at the spinal level. However, how itch information is transmitted to the brain and what central circuits underlie the itch-induced scratching behavior remain largely unknown. We found that the spinoparabrachial pathway was activated during itch processing and that optogenetic suppression of this pathway impaired itch-induced scratching behaviors. Itch-mediating spinal neurons, which express the gastrin-releasing peptide receptor, are disynaptically connected to the parabrachial nucleus via glutamatergic spinal projection neurons. Blockade of synaptic output of glutamatergic neurons in the parabrachial nucleus suppressed pruritogen-induced scratching behavior. Thus, our studies reveal a central neural circuit that is critical for itch signal processing.

Source: ScienceNOW - August 17, 2017 Category: Science Authors: Mu, D., Deng, J., Liu, K.-F., Wu, Z.-Y., Shi, Y.-F., Guo, W.-M., Mao, Q.-Q., Liu, X.-J., Li, H., Sun, Y.-G. Tags: Neuroscience reports Source Type: news