The effect of diphenylhydantoin on sleep in the cat

Abstract

1. 1. The effect of prolonged (11–24 days) administration of diphenylhydantoin (DPH) on sleep patterns of five cats was studied. 2. 2. DPH suppressed rapid eye movement (REM) sleep time significantly below pre-drug baseline levels. REM periods became shorter and less frequent. There was no consistent change in NREM sleep time. Lateral geniculate monophasic sharp wave activity during REM periods (investigated in two cats) was not markedly affected by the drug. 3. 3. Following suppression, there was no sign of the usual compensatory rebound in REM sleep time. 4. 4. DPH appears to interfere with the mechanisms responsible for REM sleep and seems to offset factors which lead to rebounds, as when REM deprivation is accomplished by other means.