title: Blood pressure lowering effect of olive is mediated through calcium channel blockade.
abstract: Olive (Olea europea) is used in traditional medicine as a remedy for hypertension. The aqueous-methanolic crude extract of O. europea fruit (OeF.Cr) was studied in anaesthetized rats and its possible mechanism was elucidated using isolated cardiovascular preparations. Intravenous administration of OeF.Cr produced a dose-dependent (30-100 mg/kg) fall in arterial blood pressure in normotensive anaesthetized rats. This effect remained unaltered in atropinized animals. In the in vitro studies OeF.Cr (0.1-3.0 mg/ml) inhibited spontaneously beating guinea-pig atria. Moreover, it relaxed K+ and/or phenylephrine-induced contractions of rabbit aortic preparations over a dose range of 0.1-3.0 mg/ml, suggesting calcium channel blockade (CCB). The CCB effect was confirmed when pretreatment of the vascular preparations with OeF.Cr produced a dose-dependent rightward shift of the Ca2+ dose-response curves, similar to verapamil. These results suggest that the blood pressure lowering effect of olive is mediated through CCB, justifying its use in hypertension.
authors.affiliation: Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi, Pakistan. anwar.gilani@aku.edu
authors.forename: Anwarul Hassan
authors.initials: AH
authors.lastname: Gilani
authors.forename: Arif-Ullah
authors.initials: AU
authors.lastname: Khan
authors.forename: Abdul Jabbar
authors.initials: AJ
authors.lastname: Shah
authors.forename: John
authors.initials: J
authors.lastname: Connor
authors.forename: Qaiser
authors.initials: Q
authors.lastname: Jabeen
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D008297:Male; D031658:Olea; D010936:Plant Extracts / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D046509:Tissue Culture Techniques
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D010936:Plant Extracts