title: Sleep disturbance among spontaneously hypertensive rats is mediated by an α1-adrenergic mechanism.
abstract: 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.
  
  
  METHODS
  Polysomnographic 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.
  
  
  RESULTS
  A 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.
  
  
  CONCLUSIONS
  α1-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.
authors: Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
authors: Terry B J
authors: TB
authors: Kuo
authors: Chun-Yu
authors: CY
authors: Chen
authors: Chun-Ting
authors: CT
authors: Lai
authors: Tsai-Yu
authors: TY
authors: Chuan
authors: Wen-Yi
authors: WY
authors: Wu
authors: Shih-Chih
authors: SC
authors: Tsai
authors: Cheryl C H
authors: CC
authors: Yang
mesh_terms: D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D008297:Male; D011224:Prazosin / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000502:physiology*; D018342:Receptors, Adrenergic, beta-1 / Q000187:drug effects / Q000502:physiology; D012890:Sleep / Q000502:physiology; D012893:Sleep Wake Disorders / Q000209:etiology* / Q000503:physiopathology
chemical_list: D018340:Receptors, Adrenergic, alpha-1; D018342:Receptors, Adrenergic, beta-1; D001262:Atenolol; D011433:Propranolol; D011224:Prazosin