European journal of pharmacology
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The purpose of the study is to find subcutaneous equianalgesic doses of memantine, amantadine and bupivacaine and use these doses to quantify the cardiovascular and central nervous system toxicity of these agents after intravenous administration. Memantine, amantadine and bupivacaine, a local anesthetic, in a dose-related fashion were determined for cutaneous analgesia by a block of the cutaneous trunci muscle reflex in rats, and equipotent doses were calculated. Following rapid intravenous infusion of equianalgesic bupivacaine, memantine, amantadine and saline (vehicle) in rats, we observed the onset time of seizure, apnea and impending death, and monitored mean arterial blood pressure and heart rate. ⋯ At equianalgesic doses, the infusion time of memantine or amantadine required to induce seizure, impending death, and apnea was longer than that of bupivacaine during rapid intravenous infusion (P<0.01). The decreasing slope in mean arterial blood pressure and heart rate was slower with memantine and amantadine when compared with bupivacaine at equivalent doses (P<0.01). Our data showed that memantine and amantadine (i) were equal to bupivacaine at producing durations of cutaneous analgesia but (ii) were less likely than bupivacaine to cause cardiovascular and central nervous system toxicity.
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Effects of fluoxetine on plasticity and apoptosis evoked by chronic stress in rat prefrontal cortex.
The prefrontal cortex is the brain region sensitive to detrimental effects of stress and even mild stress can rapidly impair its function. Aside from initiating proadaptive neuroplastic changes in the prefrontal cortex, chronic stress may also increase vulnerability of cortical neurons to apoptosis. Understanding the mechanism of plasticity and apoptotic processes is of immense importance for therapy of stress-related psychiatric disorders. ⋯ In addition, mitochondrial Bax protein was elevated by chronic social isolation, while fluoxetine failed to abolish this effect. In spite of elevated Bcl-2 in the mitochondria, the calculated Bax/Bcl-2 ratio and concomitant absence of NFκB activation pointed to initiation of apoptotic signaling in the prefrontal cortex. The results imply that fluoxetine influences plasticity in the prefrontal cortex of chronically isolated rats and fails to prevent stress-induced initiation of apoptosis in this brain structure.
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Triple reuptake inhibitors (TRIs) are potential new antidepressants, which not only enhance brain serotonin and norepinephrine concentrations but also increase dopamine levels. Therefore TRIs are believed to have faster therapeutic onset than SSRIs, and may be particularly useful for the treatment of anhedonia (i.e. inability to experience pleasure), one of the core symptoms of major depression. The current study aimed at getting better insight into the rewarding properties of DOV 216,303, which is a TRI, regarding its possible use to treat anhedonia. ⋯ DOV 216,303 decreased ICSS thresholds up to 6h after drug treatment. To our knowledge this is the first time that a triple reuptake inhibitor, DOV 216,303, induces relatively long-lasting enhancement of brain reward activity. Elevated ICSS thresholds were found after amphetamine administration, which is consistent with previously reported reward deficits induced after amphetamine-withdrawal.
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Microglial-mediated neuroinflammation is now considered to be central to the pathogenesis of various neurodegenerative processes, including Alzheimer's disease and Parkinson's disease. Therefore, rational modulation of microglia function to obtain neuroprotective effects is important for the development of safe and effective anti-inflammatory and neuroprotective agents. Here, we investigated the anti-inflammatory and neuroprotective effects, and potential molecular mechanism of action of Schisandrin B (Sch B); which is isolated from the Schizandra fruit (Schisandra chinesnesis). ⋯ Additionally, Sch B inhibited the interaction of Toll-like receptor 4 with the Toll adapter proteins MyD88, IRAK-1 and TRAF-6 resulting in an inhibition of the IKK/nuclear transcription factor (NF)-κB inflammatory signaling pathway. Furthermore, Sch B inhibited the production of reactive oxygen species (ROS) and NADPH oxidase activity in microglia. In summary, Sch B may exert neuroprotective activity by attenuating the microglial-mediated neuroinflammatory response by inhibiting the TLR4-dependent MyD88/IKK/NF-κB signaling pathway.