Rat hippocampal mossy fibers contain cholecystokinin-like immunoreactivity.
BACKGROUND
The possibility that mossy fiber endings in the rat hippocampal formation may contain cholecystokinin (CCK) was reexamined.


METHODS
For this, CCK-immunoreactivity was examined by light and electron microscopy using the avidin-biotin complex method.


RESULTS
At the light level, the topographical distribution of perikarya and processes with CCK-like immunoreactivity (CCK-LI) was similar to that previously described by others. Ultrastructural analysis of the dentate gyrus and CA3 region of the hippocampus revealed that some mossy fiber terminals contained CCK-LI most often affiliated with large, dense-core vesicles (DCV). Quantitative analysis revealed that 4-8% of the mossy terminal profiles examined (n = 350) contained CCK-labeled DCVs, which corresponded to 0.03-0.2 labeled DCVs per 100 microns2 of neuropil.


CONCLUSIONS
The presence of CCK-LI within mossy fibers in the rat suggests that there is less species variability in peptide expression in this pathway than formerly believed.
Chandy
J
J
Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021, USA.
Pierce
J P
JP
Milner
T A
TA
D000818:Animals; D002766:Cholecystokinin / Q000032:analysis*; D006624:Hippocampus / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002766:Cholecystokinin