A combined electrophysiological and morphological study of neuropeptide Y-expressing inhibitory interneurons in the spinal dorsal horn of the mouse
| Autor: | Yulia Revina, John S. Riddell, Noboru Iwagaki, Allen C. Dickie, Patricia del Río, Masahiko Watanabe, Robert P. Ganley, Erika Polgár, David Hughes, Andrew J. Todd |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Male Spinal Cord Dorsal Horn Population Green Fluorescent Proteins Mice Transgenic Biology Inhibitory postsynaptic potential Somatosensory system 03 medical and health sciences Mice Organ Culture Techniques Interneurons Whole-cell recording mental disorders Noxious stimulus Animals Humans Neuropeptide Y Green fluorescent protein Posterior Horn Cell education education.field_of_study Spinal cord musculoskeletal neural and ocular physiology Neural Inhibition Neuropeptide Y receptor humanities Electrophysiological Phenomena Mice Inbred C57BL Posterior Horn Cells Confocal microscopy Electrophysiology 030104 developmental biology Anesthesiology and Pain Medicine Neurology nervous system Female Neurology (clinical) Capsaicin Neuroscience Research Paper |
| Zdroj: | Pain |
| ISSN: | 1872-6623 |
| Popis: | Neuropeptide Y–expressing spinal inhibitory interneurons are morphologically diverse and include cells innervated by transient receptor potential vanilloid-1–negative C fibres and a subset that targets lamina III projection neurons. The spinal dorsal horn contains numerous inhibitory interneurons that control transmission of somatosensory information. Although these cells have important roles in modulating pain, we still have limited information about how they are incorporated into neuronal circuits, and this is partly due to difficulty in assigning them to functional populations. Around 15% of inhibitory interneurons in laminae I-III express neuropeptide Y (NPY), but little is known about this population. We therefore used a combined electrophysiological/morphological approach to investigate these cells in mice that express green fluorescent protein (GFP) under control of the NPY promoter. We show that GFP is largely restricted to NPY-immunoreactive cells, although it is only expressed by a third of those in lamina I-II. Reconstructions of recorded neurons revealed that they were morphologically heterogeneous, but never islet cells. Many NPY-GFP cells (including cells in lamina III) appeared to be innervated by C fibres that lack transient receptor potential vanilloid-1, and consistent with this, we found that some lamina III NPY-immunoreactive cells were activated by mechanical noxious stimuli. Projection neurons in lamina III are densely innervated by NPY-containing axons. Our results suggest that this input originates from a small subset of NPY-expressing interneurons, with the projection cells representing only a minority of their output. Taken together with results of previous studies, our findings indicate that somatodendritic morphology is of limited value in classifying functional populations among inhibitory interneurons in the dorsal horn. Because many NPY-expressing cells respond to noxious stimuli, these are likely to have a role in attenuating pain and limiting its spread. |
| Databáze: | OpenAIRE |
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