Comparative effects of pentylenetetrazol on the sensory responsiveness of lateral geniculate and reticular formation neurons.

The responses of bulbar and mesencephalic reticular formation (MRF) neurons to visual, auditory and/or somatosensory stimuli were considerably enhanced after subconvulsant doses of pentylenetetrazol (PTZ) in a similar fashion suggesting a general action of PTZ on reticular formation (RF) neurons. PTZ enhanced MRF responses evoked by electrical stimuli in the lateral geniculate nucleus (LGN) or cochlear nucleus but only modestly enhanced LGN neuronal responses. These findings indicate that the effects of this convulsant on the first brain sensory 'relay' nuclei and primary sensory receptors do not appear to be sufficient to account for the extensive PTZ-induced enhancement of RF neuronal responses, and direct effects of PTZ on the reticular formation may play a major role in this enhancement.