Division Spotlight

Nerve Cell Helpers May Be Targeted For Pain Control
Nonpainful stimulation—think rubbing your elbow after banging it on the doorway—may reduce pain by activating nerve cell colleagues called astrocytes.
The seminal “gate control theory” of pain, published in Science now over 50 years ago, has long stated that noxious signals relayed to the brain are able to be attenuated by nonpainful, large Aβ-fiber input. This formative theory focused on the neuronal aspects of spinal gating in regard to pain. However, the contribution of glia cells to pain gate control has remained unknown. In a recent study published in Science Advances, Dr. Yun Guan (Professor, Department of ACCM) and Dr. Xinzhong Dong (Professor, Department of Neuroscience) collaboratively discovered an intriguing non-neuronal gate control mechanism of physiological pain. Using state-of-the-art techniques including in vivo 2-photon calcium imaging, chemogenetic and optogenetic manipulation of spinal astrocytes, slice electrophysiology, and in vivo electrophysiology recording, they demonstrated for the first time that astrocytes in the spinal cord can be activated by nonpainful Aβ-stimulation, which subsequently inhibit the function of projecting neurons in superficial dorsal horn through astrocytic release of ATP and its derivative adenosine. These exciting findings shed new light on the role of astrocytes in the gating of pain signals, and suggest a novel non-neuronal player in the context of pain gate control, thus extending the theory beyond a strictly neuronal paradigm.