Changes in zinc content in hippocampal neurons under stress reactions of different origin

Abstract

It was shown in investigations on animals that injection of 8-(benzensulfonilamono)-quinoline (8-BSQ) in the dose 400 mg/kg was accompanied by the development in them epileptiform cramps and hippocampal intravitale reaction correlated with longing of cramps in animals. It’s intensity rose under animal stressing with physical load, immobilization, alcoholization. 8-BSQ microapplication into the hippocampus induced also the development of intravitale reaction and cramps in animals. Changes observed as a result of carried out work are explained by possibility of 8-BSQ of zinc chelating in hippocampus. The experiments used 167 mice, of which 107 mice received 8- (benzenesulfonylamino) -quinoline (8-BSQ) at a dose of 200 mg/kg, 37 mice were administered this convulsant at a dose of 400 mg/kg, and 23 mice were microapplied in hippocampus at a dose of 0.1 ml of 0.5 % solution of 8-BSQ. The analysis of the data, which is shown in this study once again supports the previously hypothesis of the role of zinc in the release of glutamic acid from the presynaptic plaque into the synaptic cleft. The complex of zinc with the chelating agent 8-BSQ affect the postsynaptic membrane thus sensitizing it. This, in turn, enhances the stimulating effect of glutamate on the postsynaptic membrane. This mechanism is accompanied not only by excessive release of glutamic acid due to the cleavage of zinc ions 8-BSQ, but also by additional sensitization of the postsynaptic membrane, which leads to increased activity of the hippocampus, up to clonic-tonic seizures. An acute pre-stress of animals through exercise, immobilization and alcoholism leads to a more pronounced intensity of the intravital reaction of 8-BSQ and to prolonged seizures. Previous administration of calcium and magnesium salts does not significantly affect the intensity of the intravital reaction and the duration of seizures in animals. And the present study elucidate that the intensity of the intravital reaction and the duration of seizures in mammals depend on the dose of the injected reagent. There is a direct relationship between the intensity of the intravital reaction and the duration of seizures in animals. Microapplication of caustic soda on which the 8-BSQ solution was prepared did not cause an intravital reaction and convulsions. These data indicate that the cause of seizures is the interaction of 8-BSQ with zinc in the neurons of the hippocampus.