TY - JOUR
T1 - Sleep disturbance among spontaneously hypertensive rats is mediated by an α1-adrenergic mechanism
AU - Kuo, Terry B J
AU - Chen, Chun Yu
AU - Lai, Chun Ting
AU - Chuan, Tsai Yu
AU - Wu, Wen Yi
AU - Tsai, Shih Chih
AU - Yang, Cheryl C H
PY - 2012/10
Y1 - 2012/10
N2 - Background Inadequate sleep may aggravate hypertension, but the pathophysiology of sleep disturbance in hypertension remains unknown. Among spontaneously hypertensive rats (SHR), sleep disturbance co-occurred with sympathetic hyperactivity; therefore, we hypothesized that the sleep disturbance can be alleviated by antagonizing the adrenergic overdrive. MethodsPolysomnographic recording was performed in SHR by telemetry. The animals were first injected with saline, and 2 days later with a hypotensive agent. Cardiac and vascular sympathetic activity were assessed using the normalized low-frequency power (LF%) of heart rate variability and the low-frequency power of arterial pressure variability (BLF), respectively.ResultsA comparison was made between the saline and hypotensive drug treatments. During quiet sleep (QS), the α1-blocker prazosin induced a significant decrease in BLF, but had no effect on LF%. The total time and bout duration of QS were lengthened and QS interruption was reduced (P 0.05 for all). When both α1-and α2-adrenoceptors were blocked by phentolamine, both BLF and LF% were lower (P 0.05 for both), but no modification to sleep structure could be observed. To antagonize Β-adrenergic activity, atenolol and propranolol were injected. The LF% after either antagonist treatment was significantly decreased; however, sleep structure was not significantly changed. The QS-promoting effect of prazosin is specific to SHR, because prazosin is ineffective when administered to Wistar-Kyoto rats.Conclusionsα1-adrenergic antagonism may reverse, at least partially, the poor sleep quality of SHR, suggesting a vicious cycle can be established between adrenergic overdrive and sleep disturbance.
AB - Background Inadequate sleep may aggravate hypertension, but the pathophysiology of sleep disturbance in hypertension remains unknown. Among spontaneously hypertensive rats (SHR), sleep disturbance co-occurred with sympathetic hyperactivity; therefore, we hypothesized that the sleep disturbance can be alleviated by antagonizing the adrenergic overdrive. MethodsPolysomnographic recording was performed in SHR by telemetry. The animals were first injected with saline, and 2 days later with a hypotensive agent. Cardiac and vascular sympathetic activity were assessed using the normalized low-frequency power (LF%) of heart rate variability and the low-frequency power of arterial pressure variability (BLF), respectively.ResultsA comparison was made between the saline and hypotensive drug treatments. During quiet sleep (QS), the α1-blocker prazosin induced a significant decrease in BLF, but had no effect on LF%. The total time and bout duration of QS were lengthened and QS interruption was reduced (P 0.05 for all). When both α1-and α2-adrenoceptors were blocked by phentolamine, both BLF and LF% were lower (P 0.05 for both), but no modification to sleep structure could be observed. To antagonize Β-adrenergic activity, atenolol and propranolol were injected. The LF% after either antagonist treatment was significantly decreased; however, sleep structure was not significantly changed. The QS-promoting effect of prazosin is specific to SHR, because prazosin is ineffective when administered to Wistar-Kyoto rats.Conclusionsα1-adrenergic antagonism may reverse, at least partially, the poor sleep quality of SHR, suggesting a vicious cycle can be established between adrenergic overdrive and sleep disturbance.
KW - β-adrenergic antagonist
KW - â-adrenergic antagonist
KW - blood pressure
KW - hypertension
KW - sleep
KW - spontaneously hypertensive rat
KW - sympathetic activity
KW - telemetry
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U2 - 10.1038/ajh.2012.93
DO - 10.1038/ajh.2012.93
M3 - Article
C2 - 22764061
AN - SCOPUS:84866354289
VL - 25
SP - 1110
EP - 1117
JO - American Journal of Hypertension
JF - American Journal of Hypertension
SN - 0895-7061
IS - 10
ER -