A critical role of sympathetic nerve regulation for the treatment of impaired daily rhythm in hypertensive Dahl rats.
There is a deep relationship between impaired circadian rhythm and hypertension. However, the detailed mechanisms between the daily sleep-wake rhythm and cardiovascular disorders have not yet been elucidated. To clarify the mechanism, we examined salt-sensitive Dahl rats that were fed normal chow (n=10), high-salt chow (n=10) and high-salt chow with bisoprolol (n=10). Simultaneous electroencephalogram, electromyogram and locomotor activity were examined to analyze the sleep-wake state. We also examined heart rate, blood pressure and echocardiographic findings to verify the presence of hypertension. Hypertension with impaired ventricular contraction was observed in the rats with high-salt-chow consumption whereas normal-chow rats did not show these disorders. Although rats with the normal diet showed a standard daily rhythm with normal rapid eye movement (REM) sleep duration and locomotor activity, the high-salt-diet group exhibited an impaired daily rhythm with suppressed REM sleep and significant abnormal locomotor activity. Bisoprolol significantly improved the daily sleep-wake rhythm and locomotor activity. We showed that an impaired daily rhythm was closely related to the development of hypertension. Regulation of sympathetic nerve alterations may have a key role in the treatment of hypertension and circadian rhythm disorder.
Suzuki
Jun-ichi
J
Department of Advanced Clinical Science and Therapeutics, University of Tokyo, 7-3-1 Hongo, Tokyo, Japan. junichisuzuki-circ@umin.ac.jp
Ogawa
Masahito
M
Tamura
Noriko
N
Maejima
Yasuhiro
Y
Takayama
Kiyoshi
K
Maemura
Koji
K
Honda
Kazuki
K
Hirata
Yasunobu
Y
Nagai
Ryozo
R
Isobe
Mitsuaki
M
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017298:Bisoprolol / Q000494:pharmacology / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D051381:Rats; D020303:Rats, Inbred Dahl; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013565:Sympatholytics / Q000494:pharmacology / Q000627:therapeutic use*; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
D000959:Antihypertensive Agents; D013565:Sympatholytics; D017298:Bisoprolol