Effects of AP5 infusion into the lateral ventricle on the activities and hippocampal electrical patterns of sleep episodes in rats.
Although N-methyl-D-aspartate (NMDA) receptors of the hippocampus are mainly associated with learning and memory that might occur "on-line" during sharp waves (SPWs) and theta-rhythm, the participation of hippocampal NMDA receptors in sleep-related processes has not been well studied. In this study, the activity of sleep episodes, hippocampal SPWs and theta-rhythm were recorded in rats received a repeated infusion of NMDA receptor antagonist, D,L-2-amino-5-phosphonopentanoic acid (AP5), into the lateral ventricle in a 5-h daytime sleep. The first trial AP5 infusion (30 mM/2 microl) did not change measures of the activity of slow wave sleep (SWS), paradoxical sleep (PS) and awake episodes, but induced a delay in the latency of the first onset of PS; in the hippocampal EEG, it increased the amplitude of SPWs within SWS and shifted the amplitude/spectral power of theta-rhythm from high to low frequency within PS. The repeated AP5 infusion augmented the activity of SWS, and impaired PS and awake episodes; in the EEG-sleep picture, it maintained high scores of SPWs with the complete blockade of theta-rhythm generation. When AP5 rat was woken, the theta-rhythm was seen during exploratory behavior. These findings provide evidence that hippocampal NMDA receptors via SPWs or directly associated with the synaptic events of theta-rhythm generation are critical for the PS activities.
Melik
Enver
E
Cukurova University, Medical Faculty, Division of Neurophysiology, Department of Physiology, 01330 Balcali, Adana/Turkey. emelik@cu.edu.tr
Babar
Emine
E
Guven
Mustafa
M
D015763:2-Amino-5-phosphonovalerate / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004569:Electroencephalography / Q000187:drug effects*; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012890:Sleep / Q000187:drug effects*; D012895:Sleep, REM / Q000187:drug effects; D013826:Theta Rhythm; D014851:Wakefulness / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D015763:2-Amino-5-phosphonovalerate