Relationship between enteric neurons and interstitial cells in the primate gastrointestinal tract.
BACKGROUND
Morphological studies have revealed a close anatomical relationship between enteric nerve terminals and intramuscular ICC (ICC-IM) which supports a role for ICC-IM as intermediaries in enteric motor neurotransmission. Recently, a second type of interstitial cell previously described as 'fibroblast-like' but can now be identified by platelet-derived growth factor receptor-α expression, has also been implicated in enteric neurotransmission in rodents. The present study was performed to determine if enteric nerve fibers form close anatomical relationships with ICC and PDGFRα(+) cells throughout the primate GI tract.


METHODS
Immunohistochemical experiments and confocal microscopy were performed to examine the relationship between excitatory and inhibitory motor neurons, ICC and PDGFRα(+) cells throughout the monkey GI tract.


RESULTS
The pan neuronal marker. Protein gene product 9.5 (PGP9.5) was used to label all enteric neurons and substance-P (sub-P) and neuronal nitric oxide synthase (nNOS) to label excitatory and inhibitory neurons, respectively. Double labeling with Kit revealed that both classes of nerve fibers were closely apposed with ICC-IM in the stomach, small intestine and colon (taenia and inter-taenia regions), but not with ICC at the level of the myenteric plexus (ICC-MY). Varicose enteric nerve fibers were closely associated with ICC-IM for distances up to 250 μm. Both excitatory and inhibitory nerve fibers were also closely apposed to PDGFRα(+) cells throughout the primate GI tract.


CONCLUSIONS
The close anatomical relationship between enteric nerve fibers and ICC-IM and PDGFRα(+) cells throughout the GI tract of the Cynomolgus monkey provides morphological evidence that these two classes of interstitial cells may provide a similar physiological function in primates as has been attributed in rodent animal models.
Department of Physiology & Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
P J
PJ
Blair
Y
Y
Bayguinov
K M
KM
Sanders
S M
SM
Ward
D000818:Animals; D003106:Colon / Q000378:metabolism; D017615:Enteric Nervous System / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000294:innervation / Q000378:metabolism*; D007150:Immunohistochemistry; D056885:Interstitial Cells of Cajal / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism; D008252:Macaca fascicularis; D008297:Male; D018613:Microscopy, Confocal; D009046:Motor Neurons / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism
D013373:Substance P; D052248:Nitric Oxide Synthase Type I; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha