TY - JOUR
T1 - Behavioral and respiratory characteristics during sleep in neonatal DBA/2J and A/J mice
AU - Balbir, Alexander
AU - Lande, Boris
AU - Fitzgerald, Robert S.
AU - Polotsky, Vsevolod
AU - Mitzner, Wayne
AU - Shirahata, Machiko
N1 - Funding Information:
The authors thank Mr. John Howell for the development of the gas delivery system as well as all other electronic devices used for this study. This work was supported by HL72293, HL81345 and AHA 0255358N. A. Balbir and R.S. Fitzgerald were supported by T32-HL07534 and HL50712, respectively.
PY - 2008/11/19
Y1 - 2008/11/19
N2 - The ventilatory response to hypoxia depends on the carotid body function and sleep-wake states. Therefore, the response must be measured in a consistent sleep-wake state. In mice, EMG with behavioral indices (coordinated movements, CMs; myoclonic twitches, MTs) has been used to assess sleep-wake states. However, in neonatal mice EMG instrumentation could induce stress, altering their behavior and ventilation. Accordingly, we examined: (1) if EMG can be eliminated for assessing sleep-wake states; and (2) behavioral characteristics and carotid body-mediated respiratory control during sleep with EMG (EMG+) or without EMG (EMG-). Seven-day-old DBA/2J and A/J mice were divided into EMG+ and EMG- groups. In both strains, CMs occurred when EMG was high; MTs were present during silent/low EMG activity. The durations of high EMG activity and of CMs were statistically indifferent. Thus, CMs can be used to indicate wake state without EMG. The stress caused by EMG instrumentation may be distinctively manifested based on genetic background. Prolonged agitation was observed in some EMG+ DBA/2J (5 of 13), but not in A/J mice. The sleep time and MT counts were indifferent between the groups in DBA/2J mice. The EMG+ A/J group showed longer sleep time and less MT counts than the EMG- A/J group. Mean respiratory variables (baseline, hyperoxic/hypoxic responses) were not severely influenced by EMG+ in either strain. Individual values were more variable in EMG+ mice. Carotid body-mediated respiratory responses (decreased ventilation upon hyperoxia and increased ventilation upon mild hypoxia) during sleep were clearly observed in these neonatal mice with or without EMG instrumentation.
AB - The ventilatory response to hypoxia depends on the carotid body function and sleep-wake states. Therefore, the response must be measured in a consistent sleep-wake state. In mice, EMG with behavioral indices (coordinated movements, CMs; myoclonic twitches, MTs) has been used to assess sleep-wake states. However, in neonatal mice EMG instrumentation could induce stress, altering their behavior and ventilation. Accordingly, we examined: (1) if EMG can be eliminated for assessing sleep-wake states; and (2) behavioral characteristics and carotid body-mediated respiratory control during sleep with EMG (EMG+) or without EMG (EMG-). Seven-day-old DBA/2J and A/J mice were divided into EMG+ and EMG- groups. In both strains, CMs occurred when EMG was high; MTs were present during silent/low EMG activity. The durations of high EMG activity and of CMs were statistically indifferent. Thus, CMs can be used to indicate wake state without EMG. The stress caused by EMG instrumentation may be distinctively manifested based on genetic background. Prolonged agitation was observed in some EMG+ DBA/2J (5 of 13), but not in A/J mice. The sleep time and MT counts were indifferent between the groups in DBA/2J mice. The EMG+ A/J group showed longer sleep time and less MT counts than the EMG- A/J group. Mean respiratory variables (baseline, hyperoxic/hypoxic responses) were not severely influenced by EMG+ in either strain. Individual values were more variable in EMG+ mice. Carotid body-mediated respiratory responses (decreased ventilation upon hyperoxia and increased ventilation upon mild hypoxia) during sleep were clearly observed in these neonatal mice with or without EMG instrumentation.
KW - Carotid body
KW - Control of breathing
KW - Electromyogram
KW - Hyperoxia
KW - Hypoxia
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U2 - 10.1016/j.brainres.2008.09.008
DO - 10.1016/j.brainres.2008.09.008
M3 - Article
C2 - 18817755
AN - SCOPUS:55549143294
SN - 0006-8993
VL - 1241
SP - 84
EP - 91
JO - Brain research
JF - Brain research
ER -