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ABSTRACT: To investigate the synergism of low-doses of amlodipine and irbesartan on reduction of blood pressure variability (BPV), amelioration of baroreflex sensitivity (BRS) and organ protection in spontaneously hypertensive rats (SHR).
The rats were administered amlodipine (1 mg·kg(-1)·d(-1)) alone, irbesartan (10 mg·kg(-1)·d(-1)) alone, or the combination of the two drugs for 4 months. The drugs were mixed into the rat chow. Blood pressure (BP) was continuously monitored in conscious animals. After the determination of BRS, the rats were killed for morphological evaluation of organ damages.
The combination of low-dose irbesartan and amlodipine had statistically significant synergism on reduction of BP and BPV, amelioration of BRS and organ protection in SHR. Multiple regression analysis showed that the decrease in left ventricular hypertrophy was associated with the decrease in systolic BPV (r=0.665, P<0.01); the decrease in aortic hypertrophy was associated with the increase in BRS (r=0.656, P<0.01); and the amelioration in renal lesion was associated with the increase in BRS (r=0.763, P<0.01) and the decrease in systolic BPV (r=0.706, P<0.01).
Long-term treatment with a combination of low-doses of amlodipine and irbesartan showed significant synergism on reduction of BP and BPV, restoration of BRS and organ protection in SHR. Besides BP reduction, the enhancement of BRS and reduction of BPV might contribute to the organ protection.
Acta Pharmacologica Sinica 08/2011; 32(9):1109-15. · 1.95 Impact Factor
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ABSTRACT: Aim: To investigate the synergism of low-doses of amlodipine and irbesartan on reduction of blood pressure variability (BPV), amelioration of baroreflex sensitivity (BRS) and organ protection in spontaneously hypertensive rats (SHR).
Acta Pharmacologica Sinica 07/2011; 32(9):1109-1115. · 1.95 Impact Factor
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ABSTRACT: To test the protective effects of betaglucin, a novel beta-glucan, on models of myocardial infarction (MI) in rats and dogs.
The left anterior descending (LAD) coronary artery occlusion model was used to induce an MI in rats and dogs. Three doses of betaglucin (10, 30 and 100 mg/kg), propranolol (positive control, 1 mg/kg) and vehicle alone (5% glucose solution) were administered before LAD occlusion, and characteristics of the resulting MI were subsequently assessed. In anesthetized dogs, blood pressure, heart rate, ventricular function, coronary artery blood flow and myocardial oxygen consumption were determined before and after the drug administration.
The MI mass in both rats and dogs was significantly reduced by betaglucin (30 and 100 mg/kg, P<0.01) and propranolol (P<0.01). In anesthetized dogs, coronary artery blood flow was increased significantly by betaglucin (30 and 100 mg/kg, P<0.01), but blood pressure, heart rate and ventricular function were not changed (P>0.05). High-dose betaglucin (100 mg/kg) increased myocardial oxygen consumption, but not to a statistically significant level (P>0.05). The hemodynamic indexes were significantly changed by propranolol.
Betaglucin has protective effects on myocardial tissue during MI in rats and dogs and has no influence on hemodynamic parameters at a therapeutic dose. The increase in coronary artery blood flow induced by betaglucin might be beneficial in the treatment of patients with MI.
Acta Pharmacologica Sinica 08/2009; 30(8):1092-8. · 1.95 Impact Factor
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ABSTRACT: Aim: To test the protective effects of betaglucin, a novel beta-glucan, on models of myocardial infarction (MI) in rats and dogs.
Acta Pharmacologica Sinica 07/2009; 30(8):1092-1098. · 1.95 Impact Factor
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ABSTRACT: 1. Aetiological studies have shown that sodium loading increases both blood pressure and death from stroke. The present study was designed to investigate the pressor and non-pressor effects of sodium loading on stroke in stroke-prone spontaneously hypertensive rats (SHRSP). 2. Eighty-five female SHRSP were used. Forty-nine SHRSP, aged 5 months, were randomly divided into two groups with or without sodium loading and their survival times were recorded. Thirty-six SHRSP, aged 3 months, were randomly divided into two groups and were instrumented to determine blood pressure, heart period and baroreflex sensitivity (BRS) after 4 months of sodium loading or normal rat chow. After determination of BRS, blood samples were collected for the measurement of tumour necrosis factor (TNF), interleukin (IL)-1beta, IL-6 and angiotensin (Ang) II and brains were dissected for light microscopic examination. 3. Over the 15 month period, the mortality of control SHRSP was 37.5%, which reached 80.0% in the sodium loading group. Compared with the control group, blood pressure was increased but BRS was significantly decreased (P < 0.001) in sodium-loaded rats. Levels of IL-1beta, IL-6 and AngII were all significantly increased (P < 0.05) in the sodium-loaded rats. Sodium loading also markedly increased the number of cerebral aneurysms. Multivariate regression analysis showed that IL-6 was the most significant factor related to aneurysm formation. 4. Sodium loading increases death from stroke in SHRSP. The increased blood pressure, impaired BRS, inflammatory reaction and the formation of cerebral aneurysms may contribute to the development of stroke.
Clinical and Experimental Pharmacology and Physiology 02/2008; 35(1):83-8. · 1.85 Impact Factor
