Activity-dependent distribution of protein kinase C-delta within rat cerebellar Purkinje cells following unilateral labyrinthectomy.

Protein kinase C isoforms PKC-delta and PKC-gamma are expressed in Purkinje cells in the uvula-nodulus of the cerebellum. We examined the effect of Purkinje cell activity on the transcription, expression and intracellular distribution of PKC-delta and PKC-gamma. Relative changes in activity were induced by unilateral labyrinthectomy (UL), decreasing the activity of Purkinje cells on the side of the labyrinthectomy relative to the contralateral side with intact vestibular input. After a UL, there was decreased immunolabeling of Purkinje cell axon terminals in the ipsilateral caudal vestibular complex by antisera to PKC-delta, but not PKC-gamma. Western blots prepared from the uvula-nodulus and caudal vestibular complex showed an increase in the cytosolic PKC-delta and a decrease in membrane-associated PKC-delta in the ipsilateral uvula-nodulus 12-48 h after the UL. Hybridization histochemistry and semiquantitative reverse transcription polymerase chain reaction (RT-PCR) demonstrated no change in transcription of PKC-delta mRNA in the uvula-nodulus 1-240 h after unilateral labyrinthectomy. We conclude that both PKC-delta and PKC-gamma are constitutively expressed in Purkinje cells. The targeting of PKC-delta, but not PKC-gamma, to Purkinje neuron synaptic terminals is influenced by activity.

Decrease in immunoreactive neutral endopeptidase in uvula epithelium of patients with obstructive sleep apnea.

The purpose of this study was to determine whether neutral endopeptidase (NEP; EC3.4.24.11) is decreased in the uvula epithelium of patients with obstructive sleep apnea (OSA). Tissues were obtained by uvulopharyngopalatoplasty in seven patients with moderate OSA and by autopsy in five individuals not known to have OSA. Using antisera to human NEP and immunoperoxidase staining, we found that NEP was localized in uvula epithelial cells of both patients with OSA and controls. However, there was a significant decrease in the number of epithelial cells staining for NEP in patients with OSA relative to controls (67 +/- 10 cells versus 261 +/- 33 cells, in 5 randomly selected high-power microscopic fields, respectively; mean +/- SEM; p < .05). The intensity of staining for NEP was similar in both groups. We conclude that immunoreactive NEP is significantly decreased in the uvula epithelium of patients with OSA.

Regional distributions of choline acetyltransferase and acetylcholinesterase activities in layers of rat cerebellar vermis.

Entire sagittal sections of rat cerebellar vermis were dissected into microgram-sized samples of molecular, granular, and white matter layers. Assayed activities of choline acetyltransferase and acetylcholinesterase were plotted back onto sectional maps of exact sample locations. On the average, the activities of choline acetyltransferase and acetylcholinesterase in the granular layer were about four and five times, respectively, those in the molecular layer. The highest activity of both enzymes was in the granular layer of the vestibulocerebellum, the nodulus and ventral uvula (lobules X and IXc of Larsell). This activity might be related to the secondary vestibulocerebellar projection, terminating as mossy fibers in the granular layer of this region. Intermediate levels of activity were found in the granular layer of the dorsal uvula (lobule IX, a and b). The lowest activities of both enzymes in the granular layer were in the culmen (lobule V). A 7.1-fold difference in choline acetyltransferase activity and a 4.5-fold difference in acetylcholinesterase activity were found between the granular layer of lobules V and X. The numerical density of aggregates of acetylcholinesterase staining product in the granular layer correlated much better with assayed acetylcholinesterase activity than with choline acetyltransferase activity.