Antihypertensive and vasorelaxant effects of ethanol extract of stem barks from Zanthoxylum rhoifolium Lam in rats.
Indian J Exp Biol
; 2013 Aug; 51(8): 661-669
Article
in En
| IMSEAR
| ID: sea-149369
ABSTRACT
Administration of ethanol extract of stem bark from Z. rhoifolium (EEtOH-ZR) induced hypotension associated with a dual effect in heart rate in normotensive rats. This response was highlighted in spontaneously hypertensive rats (SHR). In rat superior mesenteric artery rings, the cumulative addition of EEtOH-ZR (0.1–750 µg/mL) on a phenylephrine-induced pre-contraction (10-5 M) promoted a vasorelaxant effect by a concentration-dependent manner and independent of vascular endothelium. A similar effect was obtained on KCl-induced pre-contractions (80 mM). EEtOH-ZR attenuated contractions induced by cumulative addition of CaCl2 (10-6–3 × 10-2 M) in depolarizing medium without Ca2+ only at 500 or 750 µg/mL. Likewise, on S-(–)-Bay K 8644-induced pre-contractions (10-7 M), the EEtOH-ZR-induced vasorelaxant effect was attenuated. EEtOH-ZR (27, 81, 243 or 500 µg/mL) inhibited contractions induced by cumulative addition of phenylephrine (10-9 - 10-5 M) in endothelium-denuded preparations or by a single concentration (10-5 M) in a Ca2+-free medium. The involvement of K+ channels was evaluated by tetraethylammonium (3 mM); the EEtOH-ZR-induced vasorelaxation was not attenuated. Thus, calcium influx blockade through voltage-operated calcium channels (CaVL) and inhibition of calcium release from intracellular stores are probably underlying EEtOH-ZR-induced cardiovascular effects.
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Index:
IMSEAR
Main subject:
Phenylephrine
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Potassium Chloride
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Rats
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Rats, Inbred SHR
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Vasoconstrictor Agents
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Vasodilation
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Vasodilator Agents
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Blood Pressure
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Male
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Calcium Chloride
Language:
En
Journal:
Indian J Exp Biol
Year:
2013
Type:
Article