Functional remodeling of presynaptic voltage-gated calcium channels in superficial layers of the dorsal horn during neuropathic pain
Laurent Ferron,
Erika K. Harding,
Maria A. Gandini,
Craig Brideau,
Peter K. Stys,
Gerald W. Zamponi
Affiliations
Laurent Ferron
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
Erika K. Harding
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
Maria A. Gandini
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
Craig Brideau
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
Peter K. Stys
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
Gerald W. Zamponi
Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada; Corresponding author
Summary: N- and P/Q-type voltage-gated Ca2+ channels are critical for synaptic transmission. While their expression is increased in the dorsal root ganglion (DRG) neuron cell bodies during neuropathic pain conditions, less is known about their synaptic remodeling. Here, we combined genetic tools with 2-photon Ca2+ imaging to explore the functional remodeling that occurs in central presynaptic terminals of DRG neurons during neuropathic pain. We imaged GCaMP6s fluorescence responses in an ex vivo spinal cord preparation from mice expressing GCaMP6s in Trpv1-Cre lineage nociceptors. We show that Ca2+ transient amplitude is increased in central terminals of these neurons after spared nerve injury, and that this increase is mediated by both N- and P/Q-type channels. We found that GABA-B receptor-dependent inhibition of Ca2+ transients was potentiated in the superficial layer of the dorsal horn. Our results provide direct evidence toward nerve injury-induced functional remodeling of presynaptic Ca2+ channels in Trpv1-lineage nociceptor terminals.
