Lamina specific postnatal development of PKCγ interneurons within the rat medullary dorsal horn

Dev Neurobiol. 2017 Jan;77(1):102-119. doi: 10.1002/dneu.22414. Epub 2016 Jun 30.


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.

Keywords: BrdU; C-fiber; PKC gamma; medullary dorsal horn; pain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Animals, Newborn
  • Female
  • Interneurons / metabolism
  • Interneurons / physiology*
  • Male
  • Medulla Oblongata / growth & development
  • Medulla Oblongata / metabolism
  • Medulla Oblongata / physiology*
  • Protein Kinase C / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Spinal Cord Dorsal Horn / growth & development
  • Spinal Cord Dorsal Horn / metabolism
  • Spinal Cord Dorsal Horn / physiology*


  • protein kinase C gamma
  • Protein Kinase C