The role of endothelium in the vasorelaxant effects of the essential oil of  Ocimum gratissimum  in aorta and mesenteric vascular bed of rats.
This study investigated the endothelium-dependent vasorelaxant effects of the essential oil of Ocimum gratissimum (EOOG) in aortas and mesenteric vascular beds isolated from rats. EOOG (3-300 µg/mL) relaxed the tonic contractions induced by phenylephrine (0.1 µmol/L) in isolated aortas in a concentration-dependent manner in both endothelium-containing and endothelium-denuded preparations. This effect was partially reversed by L-NAME (100 µmol/L) but not by indomethacin (10 µmol/L) or TEA (5 mmol/L). In mesenteric vascular beds, bolus injections of EOOG (30, 50, 100, and 300 ng) decreased the perfusion pressure induced by noradrenaline (6 µmol/L) in endothelium-intact preparations but not in those treated with deoxycholate. L-NAME (300 µmol/L) but not TEA (1 mmol/L) or indomethacin (3 µmol/L) significantly reduced the vasodilatory response to EOOG at all of the doses tested. Our data showed that EOOG exerts a dose-dependent vasodilatory response in the resistance blood vessels of rat mesenteric vascular beds and in the capacitance blood vessel, the rat aorta. This action is completely dependent on endothelial nitric oxide (NO) release in the mesenteric vascular beds but only partially dependent on NO in the aorta. These novel effects of EOOG highlight interesting differences between resistance and capacitance blood vessels.
Laboratório de Fisio-Farmacologia da Inflamação - LAFFIN, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará (UECE), Av. Paranjana 1700, 60740-000, Fortaleza-CE, Brasil.
Alana F
AF
Pires
Socorro V Frota
SV
Madeira
Pedro M G
PM
Soares
Claudia M
CM
Montenegro
Emmanuel P
EP
Souza
Angela C
AC
Resende
Roberto
R
Soares de Moura
Ana M S
AM
Assreuy
David N
DN
Criddle
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008642:Mesenteric Veins / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000378:metabolism; D031339:Ocimum / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018924:Vascular Capacitance / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D016861:Cyclooxygenase Inhibitors; D009822:Oils, Volatile; D026902:Potassium Channel Blockers; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D009638:Norepinephrine