[Effect of excitant amino acid antagonists on glutamate receptors in the locust and on convulsions induced by glutamate, aspartate, kynurenine and quinolinic acid in mice].

All excitatory amino acid antagonists studied: diethyl esters of aspartic (DEEA) and glutamic (DEEG) acids, 2-amino-3-phosphono-propionic acid (APPA) and 2-amino-4-phosphono-butanoic acid (APBA), diminished the amplitude of excitatory postsynaptic potentials (EPP) of the locust (Locusta migratoria migratorioides) muscle fibers and arbitrary blocked glutamate (GLU) and aspartate (ASP) responses. Kynurenine (KYN) and quinolinic (QUI) acid had no effect on EPP even at a concentration of 2 X 10(-2) M. The antagonists were not strictly selective against intracerebroventricularly administered endogenous convulsants: GLU, ASP, KYN and QUI and in simulation of experimental seizures in mice.

[Miniature potentials in fast and slow muscle fibers in the locust].

The miniature excitatory postsynaptic potentials were studied in the fast and slow fibres of Locusta migratoria by means of intracellular microelectrodes. Statistical analysis indicated that the spontaneous transmitter release can be predicted by the negative binomial formula with a 85% reliability. It shows that there is certain mutual interaction between the processes responsible for the spontaneous release of the transmitter from locust nerve terminals.

[Ionic conductivity of muscle fiber membranes of Locusta migratoria].

On muscle fibers from m. flexor tibiae of the locust studies have been made of the effect of rapid changes in potassium and chloride concentrations on the membrane potential (MP). The MP constituted 56.

[Functional features of the locomotor muscles of the locust].

The ultrastructure of muscle fibres, membrane electrical constants and synaptic membrane responses to microapplication of l-glutamate were investigated in longitudinal flight muscle and flexor tibia of Locusta migratoria migratorioides. The sarcomers of the flight muscle (fast) were smaller then those of the leg muscle (slow). The effective resistances (Ro) of the flight and leg muscles were (2.