Most studies on the antihypertensive effects of bioflavonoids have
reported short-term effects (within 7 weeks) at high concentrations
(40–100 mg kg–1 day–1). The present study by contrast has investigated
long-term effects of low concentrations of bioflavonoids on
arterial blood pressure and left ventricular performance in spontaneously
hypertensive rats (SHR). Spontaneously hypertensive rats
were divided into a treated (n = 16) and a control (n = 16) group.
The treated group received daily a grape seed proanthocyanidin
extract (GSPE) at a concentration of 4mg kg–1day–1over six months.
Arterial blood pressure (ABP) was measured once monthly on six
randomly selected rats from both groups using an indirect tail-cuff
method. After three months, the remaining rats underwent
catheterizations to measure left ventricular performance and aortic
pressure. The possible role of nitric oxide (NO) in the effects of
GSPE was investigated by blocking NO synthase with N-nitro-Larginine
methyl ester (L-NAME). Animals in the treated group had
significantly lower arterial end-diastolic pressures (AEDP) after
three months of treatment compared with control animals, and this
trend continued until six months. In the treated group, left ventricular
systolic pressures (LVSP) were reduced by 16.6% (P = 0.005),
their dP/dtmax (left ventricular pressures) were reduced by 19.7%
(P = 0.050), and cardiac work was reduced by 22.0% (P = 0.045) at
the end of three months. Treatment with L-NAMEsuggested a contribution
of NO to the effects of GSPE on blood pressure. A low concentration
of GSPE administered over six months lowered AEDP
significantly, and the L-NAME response suggested that NO is
involved. The decreased AEDP had a lowering effect on left ventricular
dynamics of hypertensive rats.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1000779 |
| Date | 08 May 2008 |
| Creators | Allers, NJ, Hay, L, Schutte, PJ, Steinmann, ML, du Plooy, S, Bohmer, LH |
| Publisher | South African Journal of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | |
| Rights | South African Journal of Science |
| Relation | South African Journal of Science |
Page generated in 0.002 seconds