Protein kinase C isoforms in the enteric nervous system

Histochem Cell Biol. 2003 Jul;120(1):51-61. doi: 10.1007/s00418-003-0541-4. Epub 2003 Jun 13.


C kinases (PKCs) are a family of enzymes essential for the transduction of signals in a diverse range of cell types, including neurons. The different isoforms vary in their activation requirements. Therefore, cell-specific expression of different isoforms has implications for PKC-mediated control of organ function. This study has investigated the types and distributions of PKC isoforms in the small intestine of the guinea-pig, with particular emphasis on their localisation in myenteric neurons, using immunohistochemistry and western blotting techniques. Three PKC isoforms, gamma, eta and theta, were detected in the calbindin-immunoreactive subset of intrinsic primary afferent neurons, but not in other myenteric neurons. Both gamma and theta immunoreactivities were also located in interstitial cells of Cajal. In contrast to these isoforms, immunoreactivity for PKCs lambda and epsilon was present in all myenteric neurons of the ileum. PKCalpha immunoreactivity was detected primarily in the glial network, as shown through double labelling with antibodies to the glial filament protein, S100b. Myenteric neurons were also weakly immunoreactive for this isoform. PKCdelta immunoreactivity was very highly expressed in smooth muscle, but was largely absent from neurons. Immunoreactivity for RACK1, a binding protein for PKCbeta, was detected in both calbindin-immunoreactive neurons and in smooth muscle cells. This study indicates a selective distribution of PKC isoforms to specific cell types. Isoform-specific activity of these enzymes could provide a means through which targeted modulation of intestinal function is achieved.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diacylglycerol Kinase / analysis
  • Duodenum / enzymology
  • Enteric Nervous System / cytology
  • Enteric Nervous System / enzymology*
  • Female
  • Guinea Pigs
  • Ileum / anatomy & histology
  • Ileum / innervation
  • Immunohistochemistry
  • Isoenzymes / analysis
  • Male
  • Mice
  • Muscle, Smooth / enzymology
  • Myenteric Plexus / enzymology
  • Neuroglia / enzymology
  • Protein Kinase C / analysis*
  • Protein Kinase C / immunology
  • Protein Kinase C-epsilon
  • Rabbits
  • Receptors for Activated C Kinase
  • Receptors, Cell Surface / analysis


  • Isoenzymes
  • Receptors for Activated C Kinase
  • Receptors, Cell Surface
  • Prkce protein, mouse
  • protein kinase C nu
  • Diacylglycerol Kinase
  • Protein Kinase C
  • Protein Kinase C-epsilon