A quantitative study of neuronal nitric oxide synthase expression in laminae I–III of the rat spinal dorsal horn
| Autor: | Thomas C. P. Sardella, Masahiko Watanabe, Andrew J. Todd, Erika Polgár |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Male
VGLUT2 vesicular glutamate transporter 2 Glutamate decarboxylase nNOS neuronal nitric oxide synthase Nitric Oxide Synthase Type I confocal microscopy NADPH reduced nicotinamide adenine dinucleotide phosphate chemistry.chemical_compound GABA 0302 clinical medicine Glycine receptor GFP green fluorescent protein 0303 health sciences Microscopy Confocal General Neuroscience Cell biology Posterior Horn Cells medicine.anatomical_structure VGAT vesicular GABA transporter Excitatory postsynaptic potential GABAergic Research Paper Neuroscience(all) Blotting Western NPY neuropeptide Y nNOS Biology Inhibitory postsynaptic potential Nitric oxide 03 medical and health sciences Interneurons medicine Animals Rats Wistar GAD67 67 kDa molecular weight isoform of glutamic acid decarboxylase 030304 developmental biology NO nitric oxide NK1r neurokinin 1 receptor PKCγ Pain Mechanisms and Sensory Neuroscience inhibitory interneurons PKCγ protein kinase Cγ Spinal cord Rats chemistry nervous system cGMP cyclic guanosine monophosphate sGC soluble guanylate cyclase Neuroscience 030217 neurology & neurosurgery Immunostaining |
| Zdroj: | Neuroscience |
| ISSN: | 1873-7544 0306-4522 |
| Popis: | Nitric oxide produced by neuronal nitric oxide synthase (nNOS) in the spinal cord is required for development of hyperalgesia in inflammatory and neuropathic pain states. nNOS is expressed by some dorsal horn neurons, and an early study that used a histochemical method to identify these cells suggested that they were mainly inhibitory interneurons. We have carried out a quantitative analysis of nNOS-immunoreactivity in laminae I–III of the rat dorsal horn, to determine the proportion of inhibitory and excitatory neurons and axonal boutons that express the protein. nNOS was present in ∼5% of neurons in laminae I and III, and 18% of those in lamina II. Although most cells with strong nNOS immunostaining were GABA-immunoreactive, two-thirds of the nNOS-positive cells in lamina II and half of those in lamina III were not GABAergic, and some of these expressed protein kinase Cγ (PKCγ). We estimate that nNOS is present in 17–19% of the inhibitory interneurons in laminae I–II, and 6% of those in lamina III. However, our results suggest that nNOS is also expressed at a relatively low level by a significant proportion (∼17%) of excitatory interneurons in lamina II. nNOS was seldom seen in boutons that contained vesicular glutamate transporter 2, which is expressed by excitatory interneurons, but was co-localised with the vesicular GABA transporter (VGAT, a marker for GABAergic and glycinergic axons). nNOS was detected in 13% of VGAT boutons in lamina I and in 7–8% of those in laminae II–III. However, it was only found in 2–4% of the VGAT boutons that were presynaptic to PKCγ-expressing interneurons in this region. These results indicate that nNOS is more widely expressed than previously thought, being present in both inhibitory and excitatory neurons. They provide further evidence that axons of neurochemically defined populations of inhibitory interneuron are selective in their post-synaptic targets. Highlights ▶nNOS is expressed by nearly 20% of neurons in lamina II and 5% of those in laminae I and III. ▶The majority of nNOS neurons in laminae II and III are not GABAergic. ▶Between 7 and 13% of GABAergic boutons in laminae I–III are nNOS-immunoreactive. ▶nNOS axons form few synapses with PKCγ+ excitatory interneurons. |
| Databáze: | OpenAIRE |
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