Neuropathology of Methylmercury Intoxication
To determine the minimal toxic dose of MeHg in monkeys we administered daily 0.2 mg/kg to 4 monkeys for 56–133 days and 0.03 mg/kg to 5 monkeys for 87–331 days. It was demonstrated that 0.03 mg/kg daily (total 3.6–9.0 mg/kg) of MeHg is a toxic enough level to produce ultrastructural changes in the central nervous system.
To observe early changes in the central nervous system of monkeys and cats intoxicated with low doses of MeHg, an electron microscopic study was carried out and revealed specific ultrastructural changes in the neurons of the lateral geniculate body, calcarme cortex and in the granule cells in the cerebellum.
In order to ascertain whether the transmitter binding receptor in the central nervous system is affected in cats with or without symptoms, which were administered toxic and subclinical doses of MeHg, we examined the histological alterations associated with MeHg intoxication and then compared these with the influence of MeHg upon the binding of [3H] WB-4101, a potent alpha 1 norepinephrine receptor antagonist, to the occipital cortexes of 7 cats. We found a markedly decreased receptor affinity for alpha 1 norepinephrine in the membrane fraction of the occipital cortex intoxicated with MeHg.
KeywordsPurkinje Cell Granule Cell Occipital Cortex Cerebellar Ataxia Lateral Geniculate Body
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