Purinergic signaling between neurons and satellite glial cells of mouse dorsal root ganglia modulates neuronal excitability in vivo.
Zhiyong ChenQian HuangXiaodan SongNeil C FordChi ZhangQian XuMark LayShao-Qiu HeXinzhong DongMenachem HananiYun GuanPublished in: Pain (2021)
Primary sensory neurons in dorsal root ganglia (DRG) are wrapped by satellite glial cells (SGCs), and neuron-SGC interaction may affect somatosensation, especially nociceptive transmission. P2-purinergic receptors (P2Rs) are key elements in the two-way interactions between DRG neurons and SGCs. However, because the cell types are in such close proximity, conventional approaches such as in vitro culture and electrophysiologic recordings are not adequate to investigate the physiologically relevant responses of these cells at a population level. Here, we performed in vivo calcium imaging to survey the activation of hundreds of DRG neurons in Pirt-GCaMP6s mice and to assess SGC activation in GFAP-GCaMP6s mice in situ. By combining pharmacologic and electrophysiologic techniques, we investigated how ganglionic purinergic signaling initiated by α,β-methyleneadenosine 5'-triphosphate (α,β-MeATP) modulates neuronal activity and excitability at a population level. We found that α,β-MeATP induced robust activation of small neurons-likely nociceptors-through activation of P2X3R. Large neurons, which are likely non-nociceptive, were also activated by α,β-MeATP, but with a delay. Blocking pannexin 1 channels attenuated the late phase response of DRG neurons, indicating that P2R stimulation may subsequently induce paracrine ATP release, which could further activate cells in the ganglion. Moreover, ganglionic α,β-MeATP treatment in vivo sensitized small neurons and enhanced responses of spinal wide-dynamic-range neurons to subsequent C-fiber inputs, suggesting that modulation via ganglionic P2R signaling could significantly affect nociceptive neuron excitability and pain transmission. Therefore, targeting functional P2Rs within ganglia may represent an important new strategy for pain modulation.
Keyphrases
- spinal cord
- neuropathic pain
- induced apoptosis
- cell cycle arrest
- spinal cord injury
- signaling pathway
- stem cells
- oxidative stress
- endoplasmic reticulum stress
- cell proliferation
- chronic pain
- high resolution
- transcranial direct current stimulation
- cell death
- type diabetes
- metabolic syndrome
- pain management
- mass spectrometry
- drug delivery
- mesenchymal stem cells
- skeletal muscle
- smoking cessation
- combination therapy
- high glucose
- single molecule