title: Lamina specific postnatal development of PKCγ interneurons within the rat medullary dorsal horn.
abstract: Protein kinase C gamma (PKCγ) interneurons, located in the superficial spinal (SDH) and medullary dorsal horns (MDH), have been shown to play a critical role in cutaneous mechanical hypersensitivity. However, a thorough characterization of their development in the MDH is lacking. Here, it is shown that the number of PKCγ-ir interneurons changes from postnatal day 3 (P3) to P60 (adult) and such developmental changes differ according to laminae. PKCγ-ir interneurons are already present at P3-5 in laminae I, IIo, and III. In lamina III, they then decrease from P11-P15 to P60. Interestingly, PKCγ-ir interneurons appear only at P6 in lamina IIi, and they conversely increase to reach adult levels at P11-15. Analysis of neurogenesis using bromodeoxyuridine (BrdU) does not detect any PKCγ-BrdU double-labeling in lamina IIi. Quantification of the neuronal marker, NeuN, reveals a sharp neuronal decline (∼50%) within all superficial MDH laminae during early development (P3-15), suggesting that developmental changes in PKCγ-ir interneurons are independent from those of other neurons. Finally, neonatal capsaicin treatment, which produces a permanent loss of most unmyelinated afferent fibers, has no effect on the development of PKCγ-ir interneurons. Together, the results show that: (i) the expression of PKCγ-ir interneurons in MDH is developmentally regulated with a critical period at P11-P15, (ii) PKCγ-ir interneurons are developmentally heterogeneous, (iii) lamina IIi PKCγ-ir interneurons appear less vulnerable to cell death, and (iv) postnatal maturation of PKCγ-ir interneurons is due to neither neurogenesis, nor neuronal migration, and is independent of C-fiber development. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 102-119, 2017.
authors.affiliation: Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.
authors.forename: Noemie
authors.initials: N
authors.lastname: Mermet-Joret
authors.affiliation: Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.
authors.forename: Nadwa
authors.initials: N
authors.lastname: Chatila
authors.affiliation: Biostatistics Unit (DRCI), CHU Clermont-Ferrand, Clermont-Ferrand, F-63100, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.
authors.forename: Lénaic
authors.initials: L
authors.lastname: Monconduit
authors.affiliation: Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.|Service D'Odontologie, CHU Clermont-Ferrand, Clermont-Ferrand, F-63000, France.
authors.forename: Radhouane
authors.initials: R
authors.lastname: Dallel
authors.affiliation: Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Antri
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D007395:Interneurons / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D066148:Spinal Cord Dorsal Horn / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
chemical_list: C087857:protein kinase C gamma; D011493:Protein Kinase C
keywords: BrdU; C-fiber; PKC gamma; medullary dorsal horn; pain