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Postnatal maturation of spinal dynorphin circuits and their role in somatosensation
- Source :
- Pain
- Publication Year :
- 2020
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 2020.
-
Abstract
- Inhibitory interneurons in the adult spinal dorsal horn (DH) can be neurochemically classified into subpopulations that regulate distinct somatosensory modalities. Although inhibitory networks in the rodent DH undergo dramatic remodeling over the first weeks of life, little is known about the maturation of identified classes of GABAergic interneurons, or whether their role in somatosensation shifts during development. We investigated age-dependent changes in the connectivity and function of prodynorphin (DYN)-lineage neurons in the mouse DH that suppress mechanosensation and itch during adulthood. In vitro patch clamp recordings revealed a developmental increase in primary afferent drive to DYN interneurons and a transition from exclusive C-fiber monosynaptic input to mixed A-fiber and C-fiber innervation. Although most adult DYN interneurons exhibited tonic firing as expected from their inhibitory phenotype, neonatal and adolescent DYN cells were predominantly classified as phasic or single-spiking. Importantly, we also found that most of the inhibitory presynaptic terminals contacting lamina I spinoparabrachial projection neurons (PNs) originate from DYN neurons. Furthermore, inhibitory synaptic input from DYN interneurons onto PNs was weaker during the neonatal period, likely reflecting a lower number of GABAergic terminals and a reduced probability of GABA release compared to adults. Finally, spinal DYN interneurons attenuated mechanical sensitivity throughout development, but this population dampened acute nonhistaminergic itch only during adulthood. Collectively, these findings suggest that the spinal "gates" controlling sensory transmission to the brain may emerge in a modality-selective manner during early life due to the postnatal tuning of inhibitory synaptic circuits within the DH.
- Subjects :
- Male
Spinal Cord Dorsal Horn
Population
Dynorphin
Biology
Inhibitory postsynaptic potential
Somatosensory system
Dynorphins
Nerve Fibers, Myelinated
Article
Mice
03 medical and health sciences
0302 clinical medicine
Interneurons
030202 anesthesiology
Animals
Patch clamp
education
Nerve Fibers, Unmyelinated
education.field_of_study
Mechanosensation
Posterior Horn Cells
Anesthesiology and Pain Medicine
nervous system
Neurology
GABAergic
Female
Neurology (clinical)
Neuroscience
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 18726623 and 03043959
- Volume :
- 161
- Database :
- OpenAIRE
- Journal :
- Pain
- Accession number :
- edsair.doi.dedup.....154c391e4b1c1a9a17d59de24c722e36