Corticotropin releasing factor (CRF) modulates fear-induced alterations in sleep in mice.
Contextual fear significantly reduces rapid eye movement sleep (REM) during post-exposure sleep in mice and rats. Corticotropin releasing factor (CRF) plays a major role in CNS responses to stressors. We examined the influence of CRF and astressin (AST), a non-specific CRF antagonist, on sleep after contextual fear in BALB/c mice. Male mice were implanted with transmitters for recording sleep via telemetry and with a guide cannula aimed into the lateral ventricle. Recordings for vehicle and handling control were obtained after ICV microinjection of saline (SAL) followed by exposure to a novel chamber. Afterwards, the mice were subjected to shock training (20 trials, 0.5 mA, 0.5 s duration) for 2 sessions. After training, separate groups of mice received ICV microinjections of SAL (0.2 microl, n=9), CRF (0.4 microg, n=8), or AST (1.0 microg, n=8) prior to exposure to the shock context alone. Sleep was then recorded for 20 h (8-hour light and 12-hour dark period). Compared to handling control, contextual fear significantly decreased REM during the 8-h light period in mice receiving SAL and in mice receiving CRF, but not in the mice receiving AST. Mice receiving CRF exhibited reductions in REM during the 12-h dark period after contextual fear, whereas mice receiving SAL or AST did not. CRF also reduced non-REM (NREM) delta (slow wave) amplitude in the EEG. Only mice receiving SAL prior to contextual fear exhibited significant reductions in NREM and total sleep. These findings demonstrate a role for the central CRF system in regulating alterations in sleep induced by contextual fear.
Yang
Linghui
L
Sleep Research Laboratory, Department of Pathology and Anatomy, Eastern Virginia Medical School, P.O. Box 1980, Norfolk, VA 23501, USA.
Tang
Xiangdong
X
Wellman
Laurie L
LL
Liu
Xianling
X
Sanford
Larry D
LD
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology; D002404:Catheterization; D003214:Conditioning, Classical; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003624:Darkness; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004597:Electroshock; D004777:Environment; D005239:Fear; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008845:Microinjections; D010446:Peptide Fragments / Q000008:administration & dosage; D012890:Sleep / Q000187:drug effects / Q000502:physiology*; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology
D010446:Peptide Fragments; C104416:astressin; D003346:Corticotropin-Releasing Hormone