Cardiovascular effects induced by linalool in normotensive and hypertensive rats.
Linalool is a monoterpene alcohol and constituent of several Brazilian aromatic medicinal plants, popularly used against hypertension. Cardiovascular effects induced by linalool were evaluated. In normotensive rats, (+/-)-linalool [1, 5, 10, and 20 mg/kg body weight (BW); intravenous (i.v.)]-induced hypotension was associated with tachycardia, which was attenuated by atropine (2 mg/kg BW) and N(G)-nitro-L-arginine methyl ester (20 mg/kg BW), but was not modified after indomethacin (5 mg/kg BW) administration. In hypertensive rats, linalool [200 mg/kg BW; oral (v.o.)] reduced blood pressure without changing the heart rate. In intact rings of rat mesenteric artery precontracted with 10 microM phenylephrine, linalool (from 6.4 x 10(-6) to 6.4 x 10(-3) M) induced relaxations in a concentration-dependent manner [E(max) = (115 +/- 13)%] that were not changed after atropine administration [E(max) = (105 +/- 2)%], and were not different from those obtained in endothelium-denuded rings precontracted with phenylephrine [E(max) = (108 +/- 7)%] or 80 mM KCl [E(max) = (113 +/- 7)%] or tetraethylammonium incubation [E(max) = (105 +/- 12)%]. Linalool (1.9 x 10(-3) M) antagonized the contractions induced by CaCl2 (3 x 10(-6)-10(-2) M) (maximal inhibition, 81%). Furthermore, linalool inhibited the contractions induced by 10 microM phenylephrine or 20 mM caffeine. In conclusion, these results demonstrate that linalool reduces blood pressure probably due to a direct effect on the vascular smooth muscle leading to vasodilation.
Department of Physiology, Federal University of Sergipe, São Cristóvio - SE, Brazil.
Paulo J C
PJ
Anjos
Aline O
AO
Lima
Patrícia S
PS
Cunha
Damião P
DP
De Sousa
Alexandre S C
AS
Onofre
Thais P
TP
Ribeiro
Isac A
IA
Medeiros
Angelo R
AR
Antoniolli
Lucindo J
LJ
Quintans-Júnior
Márcio R V
MR
Santosa
D000080462:Acyclic Monoterpenes; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000188:drug therapy*; D066298:In Vitro Techniques; D008297:Male; D039821:Monoterpenes / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar
D000080462:Acyclic Monoterpenes; D039821:Monoterpenes; C018584:linalool