Region-specific alterations in insulin-like growth factor-I receptor in the central nervous system of nNOS knockout mice.
In the present study, we investigated layer-specific changes in insulin-like growth factor-I (IGF-I) receptor localization in the cerebral cortex, hippocampus and cerebellum of neuronal nitric oxide synthase knockout (nNOS-/-) mice using immunohistochemistry. In the cerebral cortex of control mice, moderately stained cells were seen through the layers II-VI in several cortical regions. In nNOS-/- mice, there was a significant decrease in IGF-I receptor immunoreactivity in the same cortical regions. In the hippocampus of control mice, a distinct immunoreactivity pattern was observed in the CA1-3 areas and dentate gyrus. The immunoreactivity for IGF-I receptor was differentially decreased in each layer in nNOS-/- mice. In nNOS-/- cerebellum, IGF-I receptor immunoreactivity was also significantly decreased in each layer of cerebellar cortex and cerebellar nuclei. To clarify whether decreased expression of IGF-I receptor in nNOS-/- mice was specific, the expression of other receptors for IGF-I was also evaluated. Receptor tyrosine kinase type A (TrkA receptor) and TrkB receptor were differentially decreased in each layer of the hippocampus or cerebellum of nNOS-/- mice. Although further studies of functional features of IGF-I systems in the nNOS-/- mice are required, our first morphological data may provide insights into NO-induced changes in trophic support as well as basic knowledge required for the study of NO-associated neurological diseases.
Department of Anatomy, College of Medicine, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul 156-756, South Korea.
Yoon Hee
YH
Chung
Kyeung Min
KM
Joo
Ryoung Hee
RH
Nam
Won Bok
WB
Lee
Kyung Hoon
KH
Lee
Choong Ik
CI
Cha
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D015536:Down-Regulation; D006624:Hippocampus / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052248:Nitric Oxide Synthase Type I; D017526:Receptor, IGF Type 1 / Q000378:metabolism*
D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496321:Nos1 protein, mouse; D017526:Receptor, IGF Type 1