TY - JOUR
T1 - Sex differences in heart rate variability during sleep following prenatal nicotine exposure in rat pups
AU - Boychuk, Carie R.
AU - Fuller, David D.
AU - Hayward, Linda F.
N1 - Funding Information:
The authors thank Mr. Jessie Stanley, Ms. Stephanie Giammalvo, Dr. Charles Wood and Lisa Fang for their technical help and the Florida Department of Health James and Esther King Biomedical Research Fund for their financial support.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2011/5/16
Y1 - 2011/5/16
N2 - The influence of both prenatal nicotine exposure (PNE; 6. mg/kg/day) and sex on heart rate (HR) regulation during sleep versus wakefulness was evaluated in 13, 16 and 26 day old rat pups. Pups were chronically instrumented at least 24. h before testing. On postnatal day 13 (P13), PNE males spent significantly more time in NREM sleep and demonstrated a greater drop in HR when transitioning from quiet wake to sleep compared to age and sex matched controls (-14 ± 5. bpm versus -1 ± 3. bpm, respectively). Heart rate variability (HRV) analysis indicated that this state-dependent drop in HR was primarily associated with a greater reduction in sympathovagal balance (LF/HF ratio) in PNE males compared to controls. No parallel changes in indices of parasympathetic drive (HF power) were identified. In contrast, no significant effect of PNE on HR during sleep versus wakefulness was identified in P13 females. However, independent of state, a significant decrease in HF power was identified in P13 PNE females compared to controls. At P16, state-dependent differences in HR or HRV between PNE and sex-matched control pups were resolved. Additionally, at P26 no significant effect of PNE on state-dependent changes in HR or HRV was identified in either sex. Analysis of the hypothalamic peptide orexin identified that PNE induced approximately a 50% reduction in hypothalamic prepro-orexin mRNA and total mRNA was lowest in PNE males. These findings suggest that PNE induces sex dependent changes in sleep related autonomic regulation of HR during early postnatal development and these changes may be related to epigenetic alterations in the orexin system.
AB - The influence of both prenatal nicotine exposure (PNE; 6. mg/kg/day) and sex on heart rate (HR) regulation during sleep versus wakefulness was evaluated in 13, 16 and 26 day old rat pups. Pups were chronically instrumented at least 24. h before testing. On postnatal day 13 (P13), PNE males spent significantly more time in NREM sleep and demonstrated a greater drop in HR when transitioning from quiet wake to sleep compared to age and sex matched controls (-14 ± 5. bpm versus -1 ± 3. bpm, respectively). Heart rate variability (HRV) analysis indicated that this state-dependent drop in HR was primarily associated with a greater reduction in sympathovagal balance (LF/HF ratio) in PNE males compared to controls. No parallel changes in indices of parasympathetic drive (HF power) were identified. In contrast, no significant effect of PNE on HR during sleep versus wakefulness was identified in P13 females. However, independent of state, a significant decrease in HF power was identified in P13 PNE females compared to controls. At P16, state-dependent differences in HR or HRV between PNE and sex-matched control pups were resolved. Additionally, at P26 no significant effect of PNE on state-dependent changes in HR or HRV was identified in either sex. Analysis of the hypothalamic peptide orexin identified that PNE induced approximately a 50% reduction in hypothalamic prepro-orexin mRNA and total mRNA was lowest in PNE males. These findings suggest that PNE induces sex dependent changes in sleep related autonomic regulation of HR during early postnatal development and these changes may be related to epigenetic alterations in the orexin system.
KW - Autonomic nervous system
KW - Hypothalamus
KW - Orexin
KW - Sexual dimorphism
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U2 - 10.1016/j.bbr.2010.12.013
DO - 10.1016/j.bbr.2010.12.013
M3 - Article
C2 - 21163307
AN - SCOPUS:78651256024
VL - 219
SP - 82
EP - 91
JO - Behavioural Brain Research
JF - Behavioural Brain Research
SN - 0166-4328
IS - 1
ER -