Sleep Research

In rats (and other rodents), chronically implanted with cortical EEG electrodes and nuchal EMG electrodes and housed in special individual sleep recording cages, we can investigate the sleep-wake pattern under different experimental conditions (e.g., light regime, sleep deprivation, drug treatment, etc). Continuous electroencephalogram (EEG) and electromyogram (EMG) recording is performed by an 18-chanel polygraph (Nihon-Kohden) over certain time periods (minutes, hours, or days). During the recording time the animals can be observed by video monitoring. Analysis of EEG and EMG records is made (a) visually by the experimenter according to standard sleep evaluation criteria, or (b) automatically by using a special computer program. Each minute (or another time interval) of the record is classified as either W (wakefulness), SWS (slow-wave sleep), or PS (paradoxical sleep, REM sleep). By further evaluation, a number of different parameters are calculated: latencies, total duration of vigilance states, number and duration of single sleep/wake episodes, time courses, etc.

Occurrence of long paradoxical sleep (PS) episodes in the sleep record of a rat during the first 4 hours after injection of the peptide ACTH 20-24, in comparison to the NaCl baseline recording 1 day before. Upper graph: NaCl (the longest PS episode was 4 min); lower graph: ACTH 20-24 (the longest PS episode was 7 min). The figure shows examples of original sleep records (EEG; EMG) and the 4-hour sleep-wake pattern (paradoxical sleep; slow wave sleep; waking), respectively, at different time scales.
  

For further information please contact:

PD Dr. Wolfram Wetzel
phone: +49(391)6263338
wetzel@ifn-magdeburg.de  
   

Recent publications:

Wetzel, W., Wagner, T., Vogel, D., Demuth, H.U., Balschun, D. Effects of the CLIP fragment ACTH 20-24 on the duration of REM sleep episodes. Neuropeptides 31, 41-45 (1997).

Wetzel W, Balschun D, Janke S, Vogel D, Wagner T.Effects of CLIP (corticotropin-like intermediate lobe peptide) and CLIP fragments on paradoxical sleep in rats.Peptides. 15, 237-41 (1994).

Wetzel W. Effect of repeated application of nootropic drugs on sleep in rats. Biomed Biochim Acta 49, 405-11 (1990).