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Localization of protein kinase C theta immunoreactivity to interstitial cells of Cajal in guinea‐pig gastrointestinal tract
Author(s) -
Southwell B. R.
Publication year - 2003
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1046/j.1365-2982.2003.00394.x
Subject(s) - interstitial cell of cajal , guinea pig , gastrointestinal tract , pathology , protein kinase c , smooth muscle , immunohistochemistry , medicine , chemistry , anatomy , biology , kinase , microbiology and biotechnology
In the gastrointestinal tract, interstitial cells of Cajal (ICC) are located between nerve fibres and muscle cells and have a role in neuromuscular transmission and muscle contractility. Protein kinase C (PKC) is involved in modulation of muscle contractility by neurotransmitters, but it is not known if PKC has a role in ICC. There are 11 different PKC isoforms. The presence of PKC isoforms in ICC in guinea‐pig gastrointestinal tract was examined using fluorescence immunohistochemistry and confocal microscopy. Segments of guinea‐pig stomach, duodenum, ileum, proximal and distal colon were fixed in zambonis fixative. Frozen sections and wholemounts were incubated with anti‐PKC antibodies ( α , β , δ , ε , γ , ι , λ , μ, θ ) followed by fluorescent secondary antibody. Only PKC theta ( θ ) immunoreactivity was found in ICC. None of the other PKC isoforms ( α , β , δ , ε , γ , ι , λ , μ) localized to the ICC. PKC θ immunoreactivity was prominent in ICC located between the circular and longitudinal muscle layers (ICC‐MY) in all regions except stomach and within the circular muscle (ICC‐IM) in the large intestine. PKC θ was not present in ICC in the deep muscular plexus in either duodenum or ileum. PKC θ immunoreactivity was present in the cell body and proximal processes of the ICC. The cells containing PKC θ also contained cKit confirming the cells were ICC. ICC‐MY in the ileum also contained the neurokinin (NK) 1 receptor. In conclusion, PKC θ is present in pacemaker ICC, but its function is not yet known. Functional studies will be needed to determine the role of this kinase in ICC. Knowing the second messenger cascades and being able to manipulate subpopulations of ICC will add to our understanding of the molecular and cell biology of ICC networks within the gastrointestinal tract and may ultimately help in understanding the aetiology of some gastrointestinal motor pathologies.