[Effect of acetylcholine, L-glutamate, serotonin and mezaton, administered microiontophoretically, on spontaneous and evoked activity of midbrain reticular formation neurons].

Spontaneous activity of reticular formation neurons responding to the stimulation of pyramidal tract axons and different peripheral conductors is liable to changes during microiontophoretic exposures to acetylcholine, L-glutamate, serotonin and mesaton. The test neurons showed the highest sensitivity to L-glutamate and acetylcholine. 80% of the neurons responded to exposures to several substances. The time course of evoked reactions in the presence of microiontophoresis of biologically active substances is uncertain in character. Different components of evoked responses might react dissimilarly to microiontophoretic application of the substances. 20% of the neurons manifested significant differences as regards the time course of evoked efferent and afferent responses.