The 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein of unknown function in vivo, is abundantly expressed in myelinating glia in two isoforms, CNP1 and CNP2. In this study, immunoblot analysis showed that CNP1 is the major isoform in adult forebrain, and that both isoforms are included in the postsynaptic density (PSD) fraction and tyrosine-phosphorylated at the basal level. However, subcellular distribution and detergent extraction data showed that CNP is nonspecifically associated with the PSD fraction. Immunocytochemistry revealed that CNP is detected, in a weak but punctate pattern, in dissociated rat hippocampal neurons of 3 days to 2 weeks in vitro. The CNP-positive punctae were distributed throughout soma and dendrites, and distinct from PSD95-positive ones. Immunoblot analysis indicated that CNP is also expressed in neuronal stem cell lines, HiB5 and F11. Interestingly, in addition to the known two isoforms, a new CNP isoform of MW 45 kDa was expressed in these cell lines and was the major type of isoform in F11 cells. Taken together, our data suggest that CNP is expressed in the early stage of in vitro development and nonspecifically included in the adult rat PSD fraction.
2',3'-Cyclic-Nucleotide Phosphodiesterases/*metabolism ; Aging/physiology ; Animals ; Cells, Cultured ; Hippocampus/cytology/metabolism ; Immunohistochemistry ; Nerve Tissue Proteins/*metabolism ; Neurons/metabolism ; Phosphotyrosine/metabolism ; Prosencephalon/cytology/*metabolism ; Rats ; Rats, Sprague-Dawley ; Substrate Specificity

OBJECTIVETo study the influence and mechanism of acute ethanol intoxication (AEI) on rat neuronal apoptosis after severe traumatic brain injury (TBI).

METHODSNinety-six Sprague-Dawley rats were randomly divided into four groups: normal control, AEI-only, TBI-only and TBI+AEI (n equal to 24 for each). Severe TBI model was developed according to Feeney's method. Rats in TBI+AEI group were firstly subjected to AEI, and then suffered head trauma. In each group, animals were sacrificed at 6 h, 24 h, 72 h, and 168 h after TBI. The level of neuronal apoptosis and the expression of Bcl-2 protein were determined by TUNEL assay and immunohistochemical method, respectively.

RESULTSApoptotic cells mainly distributed in the cortex and white matter around the damaged area. Neuronal apoptosis significantly increased at 6 h after trauma and peaked at 72 h. Both the level of neuronal apoptosis and expression of Bcl-2 protein in TBI-only group and TBI+AEI group were higher than those in control group (P less than 0.05). Compared with TBI-only group, the two indexes were much higher in TBI+AEI group at all time points (P less than 0.05).

CONCLUSIONOur findings suggest that AEI can increase neuronal apoptosis after severe TBI.

Animals ; Apoptosis ; drug effects ; Brain Injuries ; Cerebral Cortex ; cytology ; Disease Models, Animal ; Ethanol ; poisoning ; Immunohistochemistry ; In Situ Nick-End Labeling ; Male ; Neurons ; physiology ; Prosencephalon ; cytology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley