Morphology and histochemistry of the thalamus in the course of intoxication by ethyl-mercury-p-toluenesulphanilide (EMTS).

Organic Mercury compounds are known for their neurotoxicity. From our previous studies it appeared that a variable degree of damage is brought about in the individual structures of the CNS by ingestion of organic mercurials. A detailed study was undertaken on the histotopography of pathological changes occurring in the thalamus - the major integrator of various cerebral functions - following intragastric administration of EMTS, a fungicide widely applied in agriculture. Rats served as the experimental animals. They were treated intragastrically with a daily dose of 15 mg of EMTS over a period of 10 days ( the per os DL50 for rats is 100 mg/kg of body weight). The results of our study have revealed that chronic ingestion of large doses of EMTS brings about a considerable inhibition of the activities of AChE, BuTJ, acP and ATPase in many thalamic nuclei with a concomitant elevation of TPPase and NsE activities. There was considerable variation as to the degree of histoenzymatic changes in the individual thalamic nuclei. The accompanying glial reaction was evaluated aw well. An interpretation of the findings made in this study has been undertaken.