Department of Public Health, University of Szeged, H-6720 Szeged, Dóm tér 10, Hungary.
Environ Toxicol Pharmacol. 2005 May;19(3):775-84. doi: 10.1016/j.etap.2004.12.044.
The aim of this study was to see the effect of acutely administered inorganic lead, mercury, manganese, and their combinations, on the electrical activity in the somatosensory system of rats. Male Wistar rats were anaesthetised with urethane, the head was fixed in a stereotaxic frame and the left hemisphere was exposed. Weak electric shocks to the whiskers and the tail served as stimuli. Spontaneous and stimulus-evoked activity was recorded from the primary projection area of the whiskers and the tail. After an hour of control recording, one of the following was given to the rat i.p.: 1000mg/kg Pb(2+), 7mg/kg Hg(2+), 50mg/kg Mn(2+), 500mg/kg Pb(2+)+25mg/kg Mn(2+), or 500mg/kg Pb(2+)+3.5mg/kg Hg(2+). Lead caused a massive increase in the cortical response amplitude, starting immediately after administration and developing in the next 40-50min. Latency showed a minimal increase. The spontaneous activity was moderately shifted to lower frequencies. The effect of Hg(2+) on the response amplitude and on the ECoG was similar but stronger than that of Pb(2+). The effect of Mn(2+) on the evoked activity was marked but less strong than with Pb(2+). The ECoG shift was moderate. With Hg(2+) and Mn(2+), the response amplitude showed first a decrease than an increase. The effect of the Pb(2+)+Mn(2+) combination on the activities was not additive but the correlation between the alteration of the ECoG and the evoked potential was stronger than with any of the metals alone. With Pb(2+)+Hg(2+), the effect of Pb(2+) dominated on the evoked and that of Hg(2+) on the spontaneous activity. In the peripheral nerve, action potential amplitude and conduction velocity were decreased. These alterations of the spontaneous and stimulus-evoked cortical activity probably reflected a specific action of the heavy metals on the nervous activity.
本研究旨在观察急性给予无机铅、汞、锰及其混合物对大鼠体感系统电活动的影响。雄性 Wistar 大鼠用氨基甲酸乙酯麻醉，头部固定在立体定向框架中，暴露左侧大脑半球。用胡须和尾巴的弱电击作为刺激。记录胡须和尾巴的初级投射区的自发和刺激诱发活动。在控制记录 1 小时后，给大鼠腹腔内注射以下物质之一：1000mg/kg Pb(2+)、7mg/kg Hg(2+)、50mg/kg Mn(2+)、500mg/kg Pb(2+)+25mg/kg Mn(2+)或 500mg/kg Pb(2+)+3.5mg/kg Hg(2+)。铅立即给药后导致皮质反应幅度大幅增加，并在接下来的 40-50 分钟内发展。潜伏期略有增加。自发活动适度向较低频率转移。Hg(2+)对反应幅度和 ECoG 的影响与 Pb(2+)相似但更强。Mn(2+)对诱发活动的影响显著但不如 Pb(2+)强。ECoG 变化适中。Hg(2+)和 Mn(2+)使反应幅度先降低后增加。Pb(2+)+Mn(2+)组合对活性的影响不是加性的，但 ECoG 变化与诱发电位之间的相关性强于任何单一金属。Pb(2+)+Hg(2+)，Pb(2+)对诱发活动的影响占主导，Hg(2+)对自发活动的影响占主导。在周围神经中，动作电位幅度和传导速度降低。皮质自发和刺激诱发活动的这些改变可能反映了重金属对神经活动的特定作用。
