Influence of tetrodotoxin inactivation of the central nucleus of the amygdala on sleep and arousal.
OBJECTIVE
To determine the effects of temporary functional inactivation of the central nucleus of the amygdala on sleep and on activity in an arousing environment, an open field.


METHODS
Rats were implanted with electrodes for recording the electroencephalogram (EEG) and electromyogram (EMG), and with guide cannulae aimed into CNA. Sleep was recorded for 22 h (10 h light, 12 h dark) following microinjections of tetrodotoxin (TTX: 5.0 ng/0.2 microl given unilaterally [TTXUH] or bilaterally [TTXBH], and 2.5 ng/0.1 microl given bilaterally [TTXBL]) or saline (SAL) alone on separate days. Activity during 1 h in an OF was recorded after microinjections of TTXBH and SAL.


METHODS
NA.


METHODS
Three-month-old Wistar rats (n=12).


METHODS
Functional inactivation of the central nucleus of the amygdala with TTX.


RESULTS
Compared to SAL, all TTX microinjections significantly shortened NREM latency, but did not alter total NREM during either light or dark periods. During the light period, TTXBH significantly reduced total REM and REM episode number, and TTXBL decreased REM episode number. All TTX microinjections increased EEG slow wave activity (0.5-4 Hz, SWA) during wakefulness, NREM and REM. Activity in OF was decreased after TTXBH compared to SAL.


CONCLUSIONS
Functional lesions of the amygdala, including the central nucleus of the amygdala, decreased REM sleep and reduced arousal, as indicated by shortened NREM latency and decreased activity in an arousing environment. These findings suggest that the amygdala plays a broad role in modulating spontaneous sleep and wakefulness and in modulating responsiveness in arousing situations.
Tang
Xiangdong
X
Sleep Research Laboratory, Department of Pathology and Anatomy, Eastern Virginia Medical School, P.O. Box 1980, Norfolk, VA 23501, USA. Tangx@evms.edu
Yang
Linghui
L
Liu
Xianling
X
Sanford
Larry D
LD
D000679:Amygdala / Q000033:anatomy & histology* / Q000187:drug effects*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001143:Arousal / Q000187:drug effects*; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004576:Electromyography; D008297:Male; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar; D012890:Sleep / Q000187:drug effects*; D012894:Sleep Stages / Q000187:drug effects; D013779:Tetrodotoxin / Q000008:administration & dosage / Q000494:pharmacology*; D014851:Wakefulness / Q000187:drug effects
D000779:Anesthetics, Local; D013779:Tetrodotoxin