Pharmacology, biochemistry, and behavior
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Pharmacol. Biochem. Behav. · Nov 2013
Antidepressant-like activity of resveratrol treatment in the forced swim test and tail suspension test in mice: the HPA axis, BDNF expression and phosphorylation of ERK.
Resveratrol is a natural polyphenol enriched in Polygonum cuspidatum and has diverse biological activities. There is only limited information about the antidepressant-like effect of resveratrol. The present study assessed whether resveratrol treatment (20, 40 and 80mg/kg, i.p., 21days) has an antidepressant-like effect on the forced swim test (FST) and tail suspension test (TST) in mice and examined what its molecular targets might be. ⋯ Moreover, resveratrol increased brain-derived neurotrophic factor (BDNF) protein and extracellular signal-regulated kinase (ERK) phosphorylation levels in the prefrontal cortex and hippocampus. All of these antidepressant-like effects of resveratrol were essentially similar to those observed with the clinical antidepressant, fluoxetine. These results suggest that the antidepressant-like effects of resveratrol in the FST and TST are mediated, at least in part, by modulating hypothalamic-pituitary-adrenal axis, BDNF and ERK phosphorylation expression in the brain region of mice.
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Pharmacol. Biochem. Behav. · Nov 2013
Oral administration of GZ-793A, a VMAT2 inhibitor, decreases methamphetamine self-administration in rats.
Despite the high prevalence of use of methamphetamine (METH), there is no FDA-approved pharmacological treatment available currently for METH addiction. The vesicular monoamine transporter (VMAT2) has been proposed as a novel target to treat METH abuse. GZ-793A, a lobelane analog and selective VMAT2 inhibitor, has been shown previously to decrease METH self-administration specifically when administered via the subcutaneous route in rats. ⋯ The decrease in METH self-administration produced by GZ-793A (120 mg/kg) lasted at least 180 min. In contrast, GZ-793A failed to alter food-maintained responding at any of the doses or pretreatment intervals tested. The oral effectiveness and the specificity of GZ-793A to decrease methamphetamine self-administration support the feasibility of developing VMAT2 inhibitors as treatments for METH abuse.
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Pharmacol. Biochem. Behav. · Oct 2013
Transdermal delivery of cannabidiol attenuates binge alcohol-induced neurodegeneration in a rodent model of an alcohol use disorder.
Excessive alcohol consumption, characteristic of alcohol use disorders, results in neurodegeneration and behavioral and cognitive impairments that are hypothesized to contribute to the chronic and relapsing nature of alcoholism. Therefore, the current study aimed to advance the preclinical development of transdermal delivery of cannabidiol (CBD) for the treatment of alcohol-induced neurodegeneration. In Experiment 1, 1.0%, 2.5% and 5.0% CBD gels were evaluated for neuroprotection. ⋯ Experiment 2 tested a next generation 2.5% CBD gel formulation, which was compared to CBD administration by intraperitoneal injection (IP; 40.0 mg/kg/day). This experiment found similar magnitudes of neuroprotection following both routes of administration; transdermal CBD decreased FJB+ cells in the entorhinal cortex by 56.1% (p<0.05), while IP CBD resulted in a 50.6% (p<0.05) reduction in FJB+ cells. These results demonstrate the feasibility of using CBD transdermal delivery systems for the treatment of alcohol-induced neurodegeneration.
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Pharmacol. Biochem. Behav. · Oct 2013
Activation of mTOR in the spinal cord is required for pain hypersensitivity induced by chronic constriction injury in mice.
The mammalian target of rapamycin (mTOR) is known to regulate cell growth, and it also participates in pain transmission as has been recently verified in inflammatory and neuropathic pain models. The targeting of mTOR represents a new strategy for the control of chronic pain. In the present study, we investigated the effect of mTOR in the expression of PSD95 and NR2B-PSD95 or GluA2-PSD95 interaction ratio in a chronic constriction injury (CCI) mice model. ⋯ These data suggest that the mTOR pathway is activated in the spinal dorsal horn in CCI-induced neuropathic pain, and the intrathecal injection of rapamycin can reduce mechanical allodynia. Our findings indicate that spinal mTOR is an important component of CCI-induced neuropathic pain, and mTOR may be a potential target for chronic pain therapy.
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Pharmacol. Biochem. Behav. · Oct 2013
Spinal D-amino acid oxidase contributes to mechanical pain hypersensitivity induced by sleep deprivation in the rat.
We studied the hypothesis that spinal d-amino acid oxidase (DAAO) that is expressed in astrocytes and that has been reported to promote tonic pain in various pathophysiological conditions plays a role in 'physiological' pain hypersensitivity induced by rapid eye movement sleep deprivation (REMSD). The experiments were performed in healthy rats with a chronic intrathecal (i.t.) catheter. Pain behavior was assessed by determining limb withdrawal response to repetitive stimulation of the hind paw with a calibrated series of monofilaments. ⋯ CBIO (1-3 μg), sodium benzoate (30-100 μg) and AS-057278 (3-10 μg) produced dose-related antihypersensitivity effects in sleep-deprived animals. In control animals (with no sleep deprivation), the currently used doses of DAAO inhibitors failed to produce significant changes in mechanically evoked pain behavior. The results indicate that among spinal pain facilitatory mechanisms that contribute to the sleep deprivation-induced mechanical pain hypersensitivity is DAAO, presumably due to production of reactive oxygen species, such as hydrogen peroxide, an endogenous agonist of the pronociceptive TRPA1 ion channel.