Our results indicate that chronic ethanol treatment of cortical neurons resulted in decreased mRNA expression of genes involving the ubiquitin-proteasome pathway and ribosomal proteins together with mTOR expression leading to disruption of protein degradation mechanism and impairment of protein synthesis machinery.

Dentin sialophosphoprotein (DSPP) is an extracellular matrix protein that is cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) with a highly restricted expression pattern in tooth and bone. Mutations of the DSPP gene are associated with dentin genetic diseases. Regulation of tissue-specific DSPP expression has not been described. To define the molecular basis of this cell-specific expression, we characterized the promoter responsible for the cell-specific expression of the DSPP gene in odontoblasts. Within this region, DNase I footprinting and electrophoretic mobility shift assays delineated one element that contains an inverted CCAAT-binding factor site and a protein-DNA binding site using nuclear extracts from odontoblasts. A series of competitive electrophoretic mobility shift assay analyses showed that the protein-DNA binding core sequence, ACCCCCA, is a novel site sufficient for protein binding. These two protein-DNA binding sequences are conserved at the same proximal position in the mouse, rat, and human DSPP gene promoters and are ubiquitously present in the promoters of other tooth/bone genes. Mutations of the CCAAT-binding factor binding site resulted in a 5-fold decrease in promoter activity, whereas abolishment of the novel protein-DNA binding site increased promoter activity by about 4.6-fold. In contrast to DSPP, expression levels of the novel protein were significantly reduced during odontoblastic differentiation and dentin mineralization. The novel protein was shown to have a molecular mass of 72 kDa. This study shows that expression of the cell type-specific DSPP gene is mediated by the combination of inhibitory and activating mechanisms.Tooth development is a highly organized process involving complex interactions among many genes. The expression of many of these genes has been characterized during tooth development and matrix mineralization. Dentin is the principal mineralized tissue of teeth and originates from odontoblasts that synthesize and secrete collagenous and noncollagenous proteins to form the dentin extracellular matrix (ECM).1 It is believed that some noncollagenous proteins are associated at specific sites on collagen and act to promote the nucleation and growth of hydroxyapatite crystals (1). Among noncollagenous proteins, dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) are expressed at high levels in tooth (2, 3). DSP accounts for 5-8% of the dental ECM proteins with high levels of carbohydrate and sialic acid and has a resemblance to other sialoproteins such as bone sialoprotein, osteopontin, dentin matrix protein 1, and matrix extracellular phosphoglycoprotein. DPP is the major noncollageous dentin ECM protein, representing about 50% of this fraction with high aspartic acid (30 -40%) and phosphoserine (38 -50%) content suggesting a function related to dentin mineralization. In addition, DPP has an arginine-glycine-aspartic acid (RGD) sequence functional for cell attachment (4). It is thought that the DPP is the archetype of macromolecules that mi...

Dexamethasone (DEX) induces hypertension and increases the expression of tyrosine hydroxylase, the rate limiting step in catecholamine synthesis in the adrenal medulla. We have shown that DEX increases mean arterial pressure (MAP, 119 ± 0.9 mm Hg), and surgical removal of the adrenal medulla does not attenuate this response (120.4 ± 1.3 mm Hg). Our hypothesis is that DEX induces hypertension by systemic sympathetic activation. The purpose of this study was to determine the effect of sympathetic nerve ablation on DEX‐induced hypertension. Fischer 344 rats were implanted with radio‐telemetry transmitters to record MAP and heart rate (HR). After baseline recording, rats underwent chemical sympathectomy with 6‐hydroxydopamine (6‐OHDA, 20 mg/kg, i.p. for 3 days). 6‐OHDA reduced MAP by 7.2 ± 1.0 mmHg, and increased HR by 55±17 bpm. Subsequent treatment with DEX (0.1 mg/day for 7 days) elevated MAP by 12.2 ± 1.6 mmHg and reduced HR by 18±7 bpm. Similar to adrenalmedullectomy, 6‐OHDA did not abolish the hypertensive effects of DEX chronic treatment. This study will provide an insight about the role of the adrenal medulla and peripheral sympathectomy in glucocorticoid‐induced hypertension. Support provided by: Department of Veterans Affairs.

Dexamethasone (DEX) was reported to induce hypertension and increase expression of tyrosine hydroxylase (TH), the rate limiting enzymatic step in catecholamine synthesis, in the adrenal medulla. We hypothesized that: 1) DEX increases TH message in the adrenal medulla, and 2) removal of the adrenal medulla attenuates DEX‐induced hypertension. Fisher 344 rats were implanted with radio telemetry transmitters to record blood pressure and heart rate. After 5 days of baseline recording, rats were divided into 2 groups: SHAM and Adrenal medullectomy (ADMX) surgeries. Both groups received vehicle (VEH) or DEX in drinking water (0.1 mg/day for 7 days), starting 5 days after surgery. Adrenal medullas were collected from the SHAM‐VEH and SHAM‐DEX groups and RNA was isolated to quantify TH mRNA by qPCR. The results showed that TH message in DEX treated adrenal medullas increased by 5 fold. DEX increased blood pressure in SHAM‐DEX by 17± 2 mmHg and in ADMX‐DEX by 18±1 mmHg. The results of the study showed that DEX increased TH message in the adrenal medulla, but DEX‐induced hypertension was not prevented by ADMX. We conclude that DEX‐induced hypertension is not completely dependent on the adrenal medulla. Future studies will focus on the contribution of other sympathetic ganglia to DEX‐induced hypertension. Support provided by: Department of Veterans Affairs and CONACYT.