Possible involvement of indolamines in the glycogenic effect of the convulsant methionine sulfoximine in rat brain.

The aim of the present investigation was to look for the mechanisms causing disturbances in carbohydrate metabolism during the action of the epileptogenic agent methionine sulfoximine. The levels of glucose, glycogen, and indolamines were measured in seven different regions of rat brain. Methionine sulfoximine induced a decrease in serotonin level which was roughly dose-dependent. There were no obvious changes in tryptophan and 5-hydroxyindoleacetic levels in any area. Methionine sulfoximine induced the known increase in glucose and glycogen levels. The direct precursor of serotonin. 5-hydroxytryptophan, and benserazide (a decarboxylase inhibitor) were then injected into rats in association with methionine sulfoximine. In this case, methionine sulfoximine failed to induce seizures. Moreover, the serotonin level was unchanged and the carbohydrate content did not significantly increase. There was only a rise in 5-hydroxyindoleacetic acid level. This work shows a striking parallelism between serotonin decrease and glycogen increase.