title: Reassessing morphine effects in cats: II. Protracted effects on sleep-wakefulness and the EEG.
abstract: Adult cats were implanted with standard electrodes to record EEG, EOG, and EMG. After 15 days, morphine sulphate or saline placebo was given IP at 0.5, 1.0, 2.0, 3.0 mg/kg, at least 15 days apart. Cats were continuously recorded for 72 hr postinjection. Wakefulness, drowsiness, NREM and REM sleep percentages were scored from polygraphic features and statistically analysed. There was a dose-dependent suppression of NREM and REM sleep for at least 6 hours postmorphine, with a progressive sleep recovery thereafter. During the insomnia period there was an EEG/behavioral dissociation where bursts of high-voltage waves were seen over a background of desynchrony; meanwhile the animal was first aroused although quiet and later showed stereotypic behavior. There was a prolonged NREM sleep rebound which started later at the higher doses. A significant, relatively brief REM sleep rebound was seen only at the lowest dose. The latency for NREM and REM sleep onset was also dose-dependent. Possible brain sites of morphine actions and similarities with effects in other species are discussed.
mesh_terms: D000818:Animals; D002415:Cats; D004569:Electroencephalography; D006801:Humans; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D012890:Sleep / Q000187:drug effects*; D012894:Sleep Stages / Q000187:drug effects; D013239:Stereotyped Behavior / Q000187:drug effects
chemical_list: D009020:Morphine