Glycogen particles in methionine sulfoximine epileptogenic rodent brain and liver after the administration of methionine and actinomycin D.

Rats and mice were submitted either to the convulsant methionine sulfoximine (MSO) alone or to MSO combined with actinomycin D or methionine respectively. Twenty-four hours after the intraperitoneal administration of these compounds, the animals were killed and tissue samples were prepared for electron microscopy. Methionine sulfoximine induced 'grand mal' type seizures which were abolished by methionine. In saline controls, glycogen was as beta particles located in the cytoplasm of astrocytes, i.e. in perikarya and processes. Liver glycogen was as perinuclear masses of alpha and beta particles or as alpha particles scattered in all the cytoplasm. When the rodents were treated with MSO, glycogen was as alpha and beta particles which invaded all areas of the astrocyte cytoplasm, this increase being tremendous in perivascular end feet. Actinomycin D slowed down the accumulation of glycogen particles while methionine completely abolished it. In any case, glycogen particles were confined to the astrocytes and were never seen in other types of cells. In liver, MSO induced an important decrease or a complete disappearance of glycogen particles. When the convulsant was combined with actinomycin D or with methionine, the figures looked like those of controls. These results have been discussed in relation to the mechanism of glycogenesis in central nervous system of rodents submitted to MSO.