Cellular Basis of Itch Sensation
Yan-Gang Sun 1†, Zhong-Qiu Zhao 1†, Xiu-Li Meng 2, Jun Yin 1, Xian-Yu Liu 1, Zhou-Feng Chen 1*
1 Departments of Anesthesiology, Psychiatry, and Developmental Biology, Washington University School of Medicine Pain Center, St. Louis, MO 63110, USA.
2 Departments of Anesthesiology, Psychiatry, and Developmental Biology, Washington University School of Medicine Pain Center, St. Louis, MO 63110, USA.; Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, P.R. China.
- To whom correspondence should be addressed.
Zhou-Feng Chen , E-mail: chenz@wustl.edu
†These authors contributed equally to this work.
Itch and pain are two distinct sensations. Although our previous study suggested that gastrin-releasing peptide receptor (GRPR) is an itch-specific gene in the spinal cord, a long-standing question of whether there are separate neuronal pathways for itch and pain remains unsettled. Here, we selectively ablated lamina I neurons expressing GRPR in the spinal cord of mice. These mice showed profound scratching deficits in response to all of the itching (pruritogenic) stimuli tested, irrespective of their histamine-dependence. In contrast, pain behaviors were unaffected. Our data also suggest that GRPR+ neurons are different from the spinothalamic tract (STT) neurons that have been the focus of the debate. Together, the present study suggests that GRPR+ neurons constitute a long-sought labeled line for itch sensation in the spinal cord.
TRPV1-expressing primary afferents generate behavioral responses to pruritogens via multiple mechanisms. 2009
Feeling good: on the role of C fiber mediated touch in interoception. 2010
- We conclude that from the skin through the brain, C touch shares more characteristics with interoceptive modalities (e.g. pain, temperature, and itch) than exteroceptive Aβ touch, vision or hearing.
