Effect of alismol on adrenergic mechanism in isolated rabbit ear artery.
Effects of alismol, a sesquiterpenoid isolated from the rhyzome of Alisma orientale, on adrenergic mechanisms were examined in the isolated rabbit ear artery. Alismol (10(-6) to 10(-4) M) inhibited the contraction of isolated rabbit ear artery by electrical stimulation of the perivascular nerves. The inhibition was concentration-dependent; at a concentration of 10(-4) M, the inhibition was 90% (n = 8). Treatment with 10(-4) M alismol inhibited the increase in 3H-noradrenaline (3H-NAd) release induced by electrical stimulation by 63 +/- 6%. Alismol at 10(-4) M did not affect the neuronal uptake of 3H-NAd in the artery. Alismol at 10(-4) M slightly inhibited contractions induced by exogenously administered NAd. These results demonstrate that alismol inhibits the adrenergic neuro-effector mechanisms in rabbit ear artery, and they suggest that alismol acts primarily on nerve terminals and inhibits their responses to electrical stimulation by interfering with NAd release.
Matsuda
H
H
Kyoto Pharmaceutical University, Japan.
Yamahara
J
J
Kobayashi
G
G
Fujimura
H
H
Kurahashi
K
K
Fujiwara
M
M
D000818:Animals; D001158:Arteries / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D012717:Sesquiterpenes / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects*
D004365:Drugs, Chinese Herbal; D012717:Sesquiterpenes; C053720:alismol; D011433:Propranolol; D009638:Norepinephrine