Objective Ethanol is widely known for its ability to cause dramatic changes in emotion, social cognition, and behavior following systemic administration in humans. Human neuroimaging studies suggest that alcohol depen...
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Objective Ethanol is widely known for its ability to cause dramatic changes in emotion, social cognition, and behavior following systemic administration in humans. Human neuroimaging studies suggest that alcohol dependence and chronic pain may share common mechanisms through amygdala-medial prefrontal cortex(mPFC) interactions. However, whether acute administration of ethanol in the mPFC can modulate pain perception is unknown. Methods We directly microinjected the moderate dose of ethanol into the mPFC, measured its effect on pain sensitivity and further explored its pharmacological mechanisms. Results(1) We showed that bilateral microinjections of ethanol into the prelimbic and infralimbic areas of the mPFC lowered the bilateral mechanical pain threshold without influencing thermal pain sensitivity in adult rats. However, bilateral microinjections of artificial cerebrospinal fluid into the mPFC or bilateral microinjections of ethanol into motor cortex area 1 failed to do so, suggesting regional selectivity of the effects of ethanol.(2) Bilateral microinjections of ethanol did not change the expression of either pro-apoptotic(caspase-3 and Bax) or anti-apoptotic(Bcl-2) proteins, suggesting that the dose was safe and validating the method used in the current study.(3) Muscimol, a selective GABAA receptor agonist, or bicuculline, a selective GABAA receptor antagonist, was administered alone or co-administered with ethanol through the same route into the bilateral mPFC. The results showed that muscimol mimicked the effects of ethanol while bicuculline completely reversed the effects of ethanol and muscimol. Conclusion Ethanol increases mechanical pain sensitivity through activation of GABAA receptors in the mPFC of rats.
黄土的热参数是黄土灾害成因机制研究及热工计算中的重要指标,而含水率和干密度对黄土的热参数具有一定的影响。对不同含水率、不同干密度黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在常温下开展热参数试验,探讨黄...
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黄土的热参数是黄土灾害成因机制研究及热工计算中的重要指标,而含水率和干密度对黄土的热参数具有一定的影响。对不同含水率、不同干密度黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在常温下开展热参数试验,探讨黄土热参数随含水率及干密度的变化规律。研究结果表明:黄土试样含水率一定时,干密度越大,其导热系数、比热容及热扩散系数也越大;黄土试样的导热系数和比热容随含水率的增大基本呈线性规律增大;当含水率较低时,热扩散系数随含水率的增大而增大;当达到一定含水率时,热扩散系数随含水率的增大而减小;继续增大含水率,热扩散系数趋于稳定。含水率对黄土热参数的影响程度大于干密度对其热参数的影响程度。在热工计算中,可根据土体含水率和干密度动态地选择热参数。
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