Clorgyline-induced reduction in body temperature and its relationship to vigilance states in Syrian hamsters.

The antidepressant drug clorgyline, a monoamine oxidase inhibitor (MAOI) that selectively inhibits MAO type A was administered chronically to Syrian hamsters. Twenty-four-hour EEG sleep and/or telemetered peritoneal temperature were monitored during selected sampling periods over four weeks. Chronic clorgyline treatment decreased rapid-eye-movement (REM) sleep time and body temperature during the first week. Incomplete tolerance to these effects developed during the second and third weeks. REM sleep and body temperature were correlated during chronic clorgyline treatment. Non-REM (NREM) sleep was elevated throughout chronic treatment. These results suggest that clorgyline's effects on REM and NREM sleep might be related to clorgyline's effects on thermoregulation and to the development of tolerance. However, causal relationships between clorgyline's effects on thermoregulation and the levels of REM and NREM sleep remain to be determined.