Pamphlett R, Waley P
Department of Pathology, University of Sydney, NSW, Australia.
J Neurol Sci. 1996 Jan;135(1):63-7. doi: 10.1016/0022-510x(95)00258-4.
In animals, inorganic mercury can bypass the blood brain barrier and enter motor neurons. We sought to determine the lowest injected dose of mercury that could be detected in mouse motor neurons. Mice were injected intraperitoneally with mercuric chloride in doses from 0.05 to 2 micrograms/g body weight and studied between 5 days and 18 months after injection. After formalin fixation, 7 microns sections of cerebrum, cerebellum, brain stem, spinal cord and kidney were stained with silver nitrate autometallography. Five days after injection, mercury granules were detected at doses from 0.2 microgram/g upwards in the cell bodies of spinal and brain stem motor neurons, more granules being seen at the higher doses. Mercury granules were also seen in 5% of posterior root ganglion neurons. At doses from 0.05 microgram/g upwards mercury was detected 5 days later in renal tubule cells. Mercury was still present in motor neurons 6-11 months after injection, but by this time mercury had been cleared from the kidneys. Low doses of inorganic mercury are therefore selectively taken up and retained by motor neurons, making this neurotoxin a good candidate for a cause of sporadic motor neuron disease.
在动物体内，无机汞能够越过血脑屏障并进入运动神经元。我们试图确定在小鼠运动神经元中能够检测到的最低注射汞剂量。给小鼠腹腔注射氯化汞，剂量为0.05至2微克/克体重，并在注射后5天至18个月进行研究。经福尔马林固定后，将大脑、小脑、脑干、脊髓和肾脏切成7微米厚的切片，用硝酸银自动显影术染色。注射后5天，在脊髓和脑干运动神经元的细胞体中，能检测到剂量从0.2微克/克及以上的汞颗粒，剂量越高，可见的颗粒越多。在5%的后根神经节神经元中也能看到汞颗粒。剂量从0.05微克/克及以上时，5天后在肾小管细胞中检测到汞。注射后6至11个月，运动神经元中仍有汞存在，但此时肾脏中的汞已被清除。因此，低剂量的无机汞会被运动神经元选择性摄取并留存，这使得这种神经毒素成为散发性运动神经元疾病病因的一个有力候选因素。
