Amlodipine has a preventive effect on temporal left ventricular hypokinesia after emotional stress compared with an angiotensin II receptor blocker.
OBJECTIVE
We previously reported that α- and β-blockers protected against emotional stress-induced cardiac dysfunction, but the protective effects of other antihypertensive drugs is unknown. The purpose of this study is to evaluate the ability of a calcium channel blocker, amlodipine, to prevent temporal left ventricular hypokinesia after emotional stress compared with an angiotensin II receptor blocker, olmesartan medoxomil.


METHODS
Rats premedicated with amlodipine (0.2 mg/kg), olmesartan (0.8 mg/kg), or vehicle were restrained for 30 min (immobilization stress: IMO) to reproduce emotional stress and then anesthetized to release stress. We measured the fractional area change (FAC) using echocardiography (SONOS5500) with a s12 probe (frequency 5-12 MHz, frame rate 120 Hz) and blood pressure and heart rate at the end of IMO and every 10 for 60 min after IMO.


RESULTS
During IMO, FAC in the amlodipine or the olmesartan group was as high as that in the vehicle group. At 20 min after IMO, FAC in the amlodipine group was significantly higher than in the other two groups (84 ± 8 vs. 60 ± 7 or 68 ± 15 %, p < 0.05). During IMO, blood pressure in the amlodipine or the olmesartan group was significantly lower than with vehicle (119 ± 6 and 110 ± 7 vs. 124 ± 5 mmHg, p < 0.05). After IMO, blood pressure in the olmesartan group was significantly lower than in the other two groups.


CONCLUSIONS
Acute administration of amlodipine could prevent a sudden drop in cardiac function after acute stress like IMO, but olmesartan did not. Amlodipine might have a protective effect on temporal left ventricular hypokinesia after emotional stress, which might not be related to decreased blood pressure.
School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan. ishikura@sahs.med.osaka-u.ac.jp.
Fuminobu
F
Ishikura
School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Yuri
Y
Takano
Department of Anatomy and Neurobiology, Wakayama Medical University, Wakayama, Japan.
Takashi
T
Ueyama
Calcium channel blocker; Left ventricular dysfunction; Mental stress; Takotsubo (ampulla) cardiomyopathy