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Antihypertensive Action (antihypertensive + action)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Tissue distribution of antihypertensive dipeptide, Val-Tyr, after its single oral administration to spontaneously hypertensive rats

JOURNAL OF PEPTIDE SCIENCE, Issue 9 2004
Toshiro Matsui
Abstract The distribution of an antihypertensive dipeptide, Val-Tyr (VY), in the tissues of spontaneously hypertensive rats (SHR) was investigated in this study. A single oral administration of VY (10 mg/kg) to 18-week-old SHR resulted in a prolonged reduction of systolic blood pressure (SBP) up to 9 h (SBP0h198.0 ± 3.6 mmHg; SBP9h 154.6 ± 3.5 mmHg). As a result of VY determination, a roughly 10-fold higher increment of plasma VY level was observed at 1 h than that at 0 h, whereas thereafter the level declined rapidly. In tissues, VY was widely accumulated in the kidney, lung, heart, mesenteric artery and abdominal aorta with the area under the curve over 9 h of more than 40 pmol h/g tissue; of these a higher VY level was observed in the kidney and lung. In addition, a mean resident time (MRT) for each tissue (>5 h except for liver) revealed that VY preferably accumulated in the tissues rather than in the plasma (MRT 3.8 h). Significant reductions of tissue angiotensin I-converting enzyme activity and angiotensin II level were found in the abdominal aorta as well as in the kidney, suggesting that these organs could be a target site associated with the antihypertensive action of VY. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd. [source]

Iso-S -petasin, a hypotensive sesquiterpene from Petasites formosanus, depresses cardiac contraction and intracellular Ca2+ transients in adult rat ventricular myocytes

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2003
Lucy B. Esberg
ABSTRACT Petasites formosanus is an indigenous species of the medicinal plant Petasites which has been used to treat hypertension. Both S -petasin and its isoform iso-S -petasin have been shown to be the effective ingredients in P. formosanus. However, their effect on heart function has not been revealed. This study was to examine the effect of iso-S -petasin on cardiac contractile function at the myocyte level. Ventricular myocytes were isolated from adult rat hearts and were stimulated to contract at 0.5 Hz under 1.0 mm extracellular Ca2+. Contractile properties were evaluated using an lonOptix MyoCam system including peak shortening (PS), time to PS (TPS), time to 90% re-lengthening (TR90) and maximal velocity of shortening/re-lengthening (±dL/dt). Intracellular Ca2+ properties were assessed by fura-2 and presented as Ca2+ -induced Ca2+ release (CICR) and intracellular Ca2+ decay. Acute application of iso-S -petasin (10,7 to 10,4 M) elicited a concentration-dependent inhibition in PS and CICR, with maximal inhibitions of 51.0% and 31.0%, respectively. iso-S -petasin also induced a concentration-dependent inhibition of ± dL/dt without affecting TPS, TR90, baseline intracellular Ca2+ level or intracellular Ca2+ decay. Elevation of extracellular Ca2+ from 1.0 mm to 2.7 mm significantly antagonized the iso-S -petasin-induced depression in PS and CICR. These results demonstrated a direct depressant action of iso-S -petasin on ventricular contraction, which may work in concert with its antihypertensive action to reduce the cardiac load. The iso-S -petasin-induced decrease in CICR may play a role in its cardiac depressant effect. [source]

Cardiovascular effects of endothelin-1 and endothelin antagonists in conscious, hypertensive ((mRen-2)27) rats

BRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2000
S M Gardiner
SB 209670 is a potent antagonist of the vasoconstrictor (ETA - and ETB -receptor-mediated) and vasodilator (ETB -receptor-mediated) effects of endothelin, whereas SB 234551 is relatively selective for the constrictor (ETA -receptor-mediated) effects. Since we had previously found SB 209670 exerted antihypertensive, vasodilator effects in conscious, heterozygous, transgenic ((mRen-2)27) (abbreviated to TG) rats, here we compared the two antagonists in that model, and assessed their chronic effects on responses to exogenous endothelin-1. We did this to test our global hypothesis, namely, that SB 209670, but not SB 234551, would cause inhibition of the depressor effects of exogenous endothelin-1 in vivo, and that this differential effect would be associated with a more marked antihypertensive action of SB 234551 in TG rats. SB 209670 and SB 234551 (infused for 50 h) exerted similar, sustained, antihypertensive effects in TG rats. The antihypertensive effects of the antagonists occurred at times when the pressor effects of exogenous endothelin-1 were not significantly inhibited. Furthermore, SB 234551 did not exert a greater antihypertensive effect than SB 209670 at a time (i.e., 2,4 h) when the depressor effects of endothelin-1 were abolished by the latter, but not by the former (although this differential action was lost after 24 h infusion). The results caused us to reject the hypothesis that selective antagonism of the vasoconstrictor effects of endothelin-1 would result in SB 234551 exerting a greater antihypertensive effect than SB 209670 in TG rats. British Journal of Pharmacology (2000) 131, 1732,1738; doi:10.1038/sj.bjp.0703767 [source]

Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins

PHYTOTHERAPY RESEARCH, Issue 9 2008
Tania Perrinjaquet-Moccetti
Abstract Hypertension is a harmful disease factor that develops unnoticed over time. The treatment of hypertension is aimed at an early diagnosis followed by adequate lifestyle changes rather than pharmacological treatment. The olive leaf extract EFLA®943, having antihypertensive actions in rats, was tested as a food supplement in an open study including 40 borderline hypertensive monozygotic twins. Twins of each pair were assigned to different groups receiving 500 or 1000 mg/day EFLA®943 for 8 weeks, or advice on a favourable lifestyle. Body weight, heart rate, blood pressure, glucose and lipids were measured fortnightly. Blood pressure changed significantly within pairs, depending on the dose, with mean systolic differences of ,6 mmHg (500 mg vs control) and ,13 mmHg (1000 vs 500 mg), and diastolic differences of ,5 mmHg. After 8 weeks, mean blood pressure remained unchanged from baseline in controls (systolic/diastolic: 133 ± 5/77 ± 6 vs 135 ± 11/80 ± 7 mmHg) and the low-dose group (136 ± 7/77 ± 7 vs 133 ± 10/76 ± 7), but had significantly decreased for the high dose group (137 ± 10/80 ± 10 vs 126 ± 9/76 ± 6). Cholesterol levels decreased for all treatments with significant dose-dependent within-pair differences for LDL-cholesterol. None of the other parameters showed significant changes or consistent trends. Concluding, the study confirmed the antihypertensive and cholesterol-lowering action of EFLA®943 in humans. Copyright © 2008 John Wiley & Sons, Ltd. [source]