Dynamic suppression of REM sleep by parenteral administration of the serotonin-1 agonist eltoprazine.
The purpose of this study was to determine the effects of the serotonin-1 agonist eltoprazine on the control of rapid eye movement (REM) sleep. Continuous polygraph recordings were performed for 15-17 days in four adult male cats. During the first 5 control days cats received injections of 0.9% saline intraperitoneally (i.p.) twice per day (b.i.d.). Over the next 5-7 days cats received injections of 0.9% saline intraperitoneally (i.p.) twice per day (b.i.d.). Over the next 5-7 days cats received eltoprazine i.p. (1-2 mg/kg, b.i.d.). For the final 5 recovery days cats received saline alone. During the saline control period, the mean REM sleep percent was 13.8 +/- 0.91%. When eltoprazine was administered for the subsequent 5-7 days, the mean REM percent was reduced to 1.5 +/- 0.59%. During the 5-day recovery period, REM percent increased significantly (p less than 0.0001) above both control and drug injection values to a mean of 24.5 +/- 1.3% with a maximum on recovery day 1 of 28.4 +/- 2.6% (n = 4). In addition to REM suppression, eltoprazine produced other electroencephalographic changes: an increase in slow-wave sleep (S) percent without any change in overall wake (W) percent; an increase in electromyogram (EMG) amplitude; and a decrease in ponto-geniculo-occipital (PGO) wave activity. PGO wave frequency and REM% increased significantly during the recovery period. Thus our findings demonstrate REM and PGO suppression by eltoprazine and document dramatic rebound effects following its withdrawal.
Quattrochi
J J
JJ
Laboratory of Neurophysiology, Harvard Medical School, Boston, Massachusetts 02115.
Mamelak
A
A
Binder
D K
DK
Williams
J
J
Rittenhouse
C
C
Hobson
J A
JA
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002415:Cats; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000187:drug effects*; D006801:Humans; D007274:Injections, Intraperitoneal; D008297:Male; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D012894:Sleep Stages / Q000187:drug effects* / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects* / Q000502:physiology; D013238:Stereotaxic Techniques
D010879:Piperazines; C063828:eltoprazine