[The effect of hydrocortisone on posttetanic potentiation in rat cerebral cortex slices and the molecular mechanisms of this effect].

The effect of hydrocortisone on posttetanic potentiation, Ca exchange, metabolism of phosphoinositides and phospholipids methylation, was studied. Hydrocortisone (10(-4) M) facilitated and prolonged the posttetanic potentiation. Incubation of slices in hydrocortisone for 90 sec elevated the incorporation of 32P-orthophosphate in polyphosphoinositide. Within 2 min of hydrocortisone action, the rate constant of Ca entry increased two-fold, transmembrane exchange fluxes of Ca increasing, too. Incorporation of 14C-methyl group in different phospholipids was considerably increased after 20-min hydrocortisone action.