[Reticular inhibition of evoked potentials of the ventro-basal thalamus and somatosensory cortex of the rat brain].

In rats immobilized with d-tubocurarine conditioning electrical stimulation (100/s, 300 ms) of the central grey matter, reticular formation of the midbrain and medulla depressed focal potentials in thalamic ventro-basal complex and somatosensory cortex evoked by electrical stimulation of the forelimb or medial meniscus. The average threshold current for conditioning stimulation of these structures was 70, 100 and 120 muA. A comparison of intensity and duration of evoked potentials depression (for two-fold threshold stimulation of the brain stem) is failed to detect any difference between the stimulated structures: immediately after conditioning stimulation the amplitude of the cortical evoked potentials and post-synaptic components of the evoked potentials in the ventro-basal complex were 50-60% less than control amplitude (p less than 0.01) the depression persisting for 0.5-1 s. The presynaptic component of the thalamic evoked potentials was depressed only after three five-fold threshold conditioning stimulation. The brain stem stimulation did not cause any facilitatory effect on focal potentials evoked by maximal and submaximal stimulation of the forelimb or medial lemniscus.