Sleep and medial reticular unit responses to protein synthesis inhibitors: Effects of chloramphenicol and thiamphenicol

Abstract This study utilized a newly developed combination push-pull cannula/microdrive-microwire device to record single-unit activity within the diffusion field of substances introduced into the brainstem. Single unit activity within the midbrain and pontine medial reticular formation (RF) and sleep were recorded following either perfusion or oral administration of protein synthesis inhibitors, chloramphenicol and thiamphenicol. Chloramphenicol administration led to significant reductions in the frequency, but not the duration, of individual REM episodes without altering slow-wave sleep. During control experiments in slow-wave sleep, incipient REM was characterized by substantial increases in medial RF unit activity which occurred in association with the appearance of PGO spikes. On the other hand, discharge rates of medial RF neurons were markedly attenuated by chloramphenicol but were not consistently affected by thiamphenicol. These findings suggest that reduced unit activity contributes to the REM-suppressive effects of protein synthesis inhibitors.