Potent N-methyl-D-aspartate (NMDA) receptor antagonists decrease volitional consumption of ethanol by rats. This study examined the effects of memantine, a low-affinity, open channel NMDA antagonist, on volitional consumption of ethanol by alcohol-preferring rats and potential locomotor, sedative and hypothermic effects. Volitional consumption of ethanol in a 24-hr two-choice paradigm was determined for male Myers' high-ethanol-preferring (mHEP) rats. Effects of memantine (0.3, 1.0, 3.0 and 10.0 mg ⁄ kg, i.p., b.i.d. [twice daily] for 3 days) or vehicle on volitional consumption of ethanol, proportion of ethanol to total fluids consumed, total fluid intake and consumption of food were observed. Potential sedating and locomotor effects of memantine (10.0 mg ⁄ kg, i.p., b.i.d.) were determined using an elevated plus maze and an Auto-Track Opto-Varimex activity monitoring system. Rectal temperature was measured to determine if memantine (10.0 mg ⁄ kg, i.p.) produces a hypothermic effect. The results indicate that memantine dose-dependently decreased the amount of ethanol and proportion of ethanol to total fluids consumed daily, reaching 48% and 24%, respectively, at the highest dose. These effects did not appear to be anti-caloric. Memantine (10.0 mg ⁄ kg) partially reversed both the sedation and the reductions in locomotor activity induced by ethanol. This dose did, however, produce a small, partially reversible hypothermic effect. In conclusion, memantine may decrease ethanol consumption with fewer side effects than other NMDA receptor antagonists, such as phencyclidine (PCP), MK 801 and ketamine.In the Diagnostic and Statistical Manual, 4th Edition (DSM-IV), the American Psychiatric Association has defined alcohol abuse and alcohol dependence as maladaptive patterns of alcohol use leading to clinically significant impairment or distress [1]. Cloninger and colleagues [2] have divided alcoholism into two subtypes based on distinct alcohol-related symptoms, personality traits, ages of onset and patterns of inheritance. Type 1 alcoholics are characterized by anxious (passive-dependent) personality traits and rapid development of tolerance and dependence on the anti-anxiety effects of alcohol. These drinkers lose control, have difficulty ending binges once they begin, feel guilty and experience liver complications following socially encouraged exposure to alcohol use. Type 2 alcoholics are characterized by anti-social personality traits and persistent seeking of alcohol for its euphoriant effects. These drinkers experience an early onset of inability to abstain entirely from alcohol use and are involved in fighting and arrests when drinking [2].Ethanol inhibits glutamatergic neurotransmission at the ionotropic N-methyl-d-aspartate (NMDA) receptor [3][4][5][6] which suggests that NMDA antagonists may be effective drugs for treating alcohol dependence and ⁄ or alcohol abuse. Previously, our laboratory demonstrated that LY 274614, a competitive NMDA antagonist, dizocilpine (MK 801), a non-competitive NMDA rece...

Complete artificial saliva (CAS) is a saliva substitute often used as a vehicle for test articles, including smokeless tobacco products. In the course of a study employing normal adult human dermal fibroblasts (HDFa) as a model in vitro, we discovered that CAS as a vehicle introduced a significant change in the expression of proinflammatory cytokines. To determine the effects of CAS on gene expression, real-time quantitative reverse-transcriptase PCR gene array analysis was used. Results indicate that robust changes in the expression of the proinflammatory cytokine interleukin 8 (IL8) and the vascular cell adhesion molecule 1 (VCAM1) occur within 5h of exposure to CAS. To determine whether CAS also alters cytokine release into the culture media, cytometric bead array assays for human inflammatory cytokines were performed. Analysis shows that CAS induced the release of IL8 and IL6. This study focused on determining which components in CAS were responsible for the proinflammatory response in HDFa. The following components were investigated: α-amylase, lysozyme, acid phosphatase, and urea. Results demonstrated that enzymatically active α-amylase induced gene expression for proinflammatory cytokines IL8, IL6, tumor necrosis factor-α, and IL1α and for VCAM1. Therefore, it is important to carefully evaluate the "vehicle effects" of CAS and its components in in vitro toxicology research.

Skin fibroblasts comprise the first barrier of defense against wounds, and tobacco products directly contact the oral cavity. Cultured human dermal fibroblasts were exposed to smokeless tobacco extract (STE), total particulate matter (TPM) from tobacco smoke, or nicotine at concentrations comparable to those found in these extracts for 1 h or 5 h. Differences were identified in pathway-specific genes between treatments and vehicle using qRT-PCR. At 1 h, IL1α was suppressed significantly by TPM and less significantly by STE. Neither FOS nor JUN was suppressed at 1 h by tobacco products. IL8, TNFα, VCAM1, and NFκB1 were suppressed after 5 h with STE, whereas only TNFα and NFκB1 were suppressed by TPM. At 1 h with TPM, secreted levels of IL10 and TNFα were increased. Potentially confounding effects of nicotine were exemplified by genes such as ATF3 (5 h), which was increased by nicotine but suppressed by other components of STE. Within 2 h, TPM stimulated nitric oxide production, and both STE and TPM increased reactive oxygen species. The biological significance of these findings and utilization of the gene expression changes reported herein regarding effects of the tobacco product preparations on dermal fibroblasts will require additional research.

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Complete artificial saliva (CAS) is a saliva substitute often used as a solvent control/vehicle for test reagents. In cultured normal human dermal fibroblasts incubated for 5 hours with CAS, gene expression for proinflammatory cytokines including interleukin 8 (IL8) and interleukin 1á (IL1á) was increased. Expression of vascular cell adhesion molecule 1 (VCAM1), a gene upregulated by certain proinflammatory cytokines including IL1á, was also increased. Furthermore, cytometric bead array assays indicate that CAS increased the release of proinflammatory cytokines including IL8 into the cell culture media. These results suggest that constituents of CAS may induce a proinflammatory response in cultured human dermal fibroblasts. Therefore, it is important to carefully evaluate/consider the “vehicle effects” of CAS and its constituents in oral/dental research. Funded by RJ Reynolds Golberg Postdoctoral Fellowship to GEM.