Ginger lowers blood pressure through blockade of voltage-dependent calcium channels.
Ginger (Zingiber officinale Roscoe), a well-known spice plant, has been used traditionally in a wide variety of ailments including hypertension. We report here the cardiovascular effects of ginger under controlled experimental conditions. The crude extract of ginger (Zo.Cr) induced a dose-dependent (0.3-3 mg/kg) fall in the arterial blood pressure of anesthetized rats. In guinea pig paired atria, Zo.Cr exhibited a cardiodepressant activity on the rate and force of spontaneous contractions. In rabbit thoracic aorta preparation, Zo.Cr relaxed the phenylephrine-induced vascular contraction at a dose 10 times higher than that required against K (80 mM)-induced contraction. Ca2+ channel-blocking (CCB) activity was confirmed when Zo.Cr shifted the Ca2+ dose-response curves to the right similar to the effect of verapamil. It also inhibited the phenylephrine (1 microM) control peaks in normal-Ca2+ and Ca2+-free solution, indicating that it acts at both the membrane-bound and the intracellular Ca2+ channels. When tested in endothelium-intact rat aorta, it again relaxed the K-induced contraction at a dose 14 times less than that required for relaxing the PE-induced contraction. The vasodilator effect of Zo.Cr was endothelium-independent because it was not blocked by L-NAME (0.1 mM) or atropine (1 microM) and also was reproduced in the endothelium-denuded preparations at the same dose range. These data indicate that the blood pressure-lowering effect of ginger is mediated through blockade of voltage-dependent calcium channels.
Ghayur
Muhammad Nabeel
MN
Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi, Pakistan.
Gilani
Anwarul Hassan
AH
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D020939:Zingiber officinale; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D027343:Rhizome; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D010936:Plant Extracts