PMID- 19590505
OWN - NLM
STAT- MEDLINE
DCOM- 20091207
LR  - 20121115
IS  - 1348-4214 (Electronic)
IS  - 0916-9636 (Linking)
VI  - 32
IP  - 8
DP  - 2009 Aug
TI  - Direct action of an angiotensin II receptor blocker on angiotensin II-induced 
      left atrial conduction delay in spontaneously hypertensive rats.
PG  - 721-6
LID - 10.1038/hr.2009.89 [doi]
AB  - In this study, the inhibitory action of angiotensin II (Ang II) receptor blocker 
      (ARB) on Ang II-induced conduction blocking in the left atrium was studied. 
      Transmembrane action potentials and effective refractory period (ERP) were 
      recorded from the left atrial trabeculae of spontaneously hypertensive rats 
      (SHR(Izm)s) that had been treated with or without olmesartan medoxomil (AT1 
      receptor blocker, 3.0 mg kg(-1)) for 8 weeks before the recording. During rapid 
      electrical stimulation (RES), changes in activation time (AT) and frequencies of 
      the conduction block were studied under perfusion of Ang II (10(-8) M) or Ang II 
      plus ARB (10(-7) M). Interstitial fibrosis in the left atrium was quantitatively 
      assessed using histological sections. Although action potential parameters and 
      ERP did not differ between the two groups when preparations were driven with a 
      basic cycle length, an Ang II-induced conduction delay was observed during RES, 
      and this was significantly suppressed in SHR(Izm)s treated with ARB (P<0.05). The 
      Ang II-induced conduction block was also significantly reduced with perfusion of 
      ARB (P<0.05). The interstitial fibrous area was significantly larger in untreated 
      SHR(Izm)s than in treated animals (P<0.01). This antagonizing action of AT1 
      blockade might contribute to its non-antiarrhythmic therapeutic effect on atrial 
      fibrillation because of its indirect and direct actions on the structural and 
      functional remodeling of the left atrium.
FAU - Matsuyama, Narihisa
AU  - Matsuyama N
AD  - Department of Cardiology, Yamato Municipal Hospital, Yamato 242-8602, Kanagawa, 
      Japan. yamamoto-clinic@jcom.home.ne.jp
FAU - Tsutsumi, Takeshi
AU  - Tsutsumi T
FAU - Kubota, Nami
AU  - Kubota N
FAU - Nakajima, Toshiaki
AU  - Nakajima T
FAU - Suzuki, Hiroshi
AU  - Suzuki H
FAU - Takeyama, Youici
AU  - Takeyama Y
LA  - eng
PT  - Journal Article
DEP - 20090710
PL  - England
TA  - Hypertens Res
JT  - Hypertension research : official journal of the Japanese Society of Hypertension
JID - 9307690
RN  - 0 (Angiotensin II Type 1 Receptor Blockers)
RN  - 0 (Imidazoles)
RN  - 0 (Tetrazoles)
RN  - 11128-99-7 (Angiotensin II)
RN  - 8W1IQP3U10 (olmesartan)
SB  - IM
MH  - Action Potentials/drug effects
MH  - Angiotensin II/*antagonists & inhibitors/*pharmacology
MH  - Angiotensin II Type 1 Receptor Blockers/*pharmacology
MH  - Animals
MH  - Blood Pressure/drug effects
MH  - Electric Stimulation
MH  - Heart Atria/drug effects
MH  - Heart Conduction System/*drug effects
MH  - Hypertension/*drug therapy/genetics/pathology/physiopathology
MH  - Imidazoles/pharmacology
MH  - Male
MH  - Myocardium/pathology
MH  - Rats
MH  - Rats, Inbred SHR
MH  - Rats, Inbred WKY
MH  - Tetrazoles/pharmacology
EDAT- 2009/07/11 09:00
MHDA- 2009/12/16 06:00
CRDT- 2009/07/11 09:00
PHST- 2009/07/11 09:00 [entrez]
PHST- 2009/07/11 09:00 [pubmed]
PHST- 2009/12/16 06:00 [medline]
AID - hr200989 [pii]
AID - 10.1038/hr.2009.89 [doi]
PST - ppublish
SO  - Hypertens Res. 2009 Aug;32(8):721-6. doi: 10.1038/hr.2009.89. Epub 2009 Jul 10.