Thomas Schiffelholz | PubMed Health

PubMed2004

Perinatal MK-801 treatment affects age-related changes in locomotor activity from childhood to later adulthood in rats.

Neuronal degeneration underlying the pathology of schizophrenia is already present during childhood. However, most of these studies were done in adult humans or animals. The present study therefore investigated age-related changes of behavior in an innovative version of the Open Field Maze following perinatal chronic administration of the noncompetitive N-methyl-D-aspartate antagonist MK-801. The waxing and waning pattern of locomotor activity during aging with a peak around the age of 90 days was profoundly attenuated by MK-801. MK-801 further reduced locomotion and body weight in mature rats. However, it increased explorative behavior in immature rats. Therefore, the chronic perinatal administration of MK-801 seems to be a model to investigate the pathological mechanisms of psychomotor retardation and body weight dysregulation in schizophrenia.

Age Factors↗

PubMed2002

Novel object presentation affects sleep-wake behavior in rats.

Sleep is suggested to be crucial for the processing and storage of new information. Several learning tasks have been shown to increase the amount of rapid eye movement sleep (REMS) with its typical theta activity (6-8 Hz) relative to total sleep time. Vice versa, REMS deprivation is able to affect memory consolidation following some, but not all learning tasks. Furthermore, recent studies have shown an increase of spindle activity (12-15 Hz) within the electroencephalogram (EEG) of nonREMS as well. The enhancement of both spindle and theta activity is suggested to serve as background activity for the synchronization of those neuronal pathways that were involved in the registration and, later on, participate in the long-term storage of new information in defined brain regions. In the present study, the presentation of a novel object to rats enhanced the amount of preREMS, an intermediate sleep stage with high spindle activity, within the first 2 h of the subsequent sleeping phase. Four hours later, the amount of REMS was increased as well. However, there were no changes in the EEG power spectra of nonREMS, preREMS and REMS. We therefore hypothesize that the increase of preREMS and REMS amounts and the related spindle and theta activity stand for the processing and storage of new information about the presented novel objects.

Action Potentials↗