Cardiovascular effects of Nemopilema nomurai (Scyphozoa: Rhizostomeae) jellyfish venom in rats.
Over the past few years, populations of the giant jellyfish Nemopilema nomurai (Scyphozoa: Rhizostomeae) have increased dramatically in the waters of China, Korea, and Japan without any definitive reason. This has resulted in severe damage to fisheries in the areas. During a pilot study, we observed that the venom of N. nomurai produced a functional cardiac depression in mice. However, the mechanism of action was not examined. In the present study, we investigated the cardiovascular effects of nematocyst-derived venom from N. nomurai in anesthetized rats. Venom (0.1-2.4 mg protein/kg, i.v.) produced dose-dependent hypotension (65+/-12% of initial at a cumulative dose of 3 mg/kg) and bradycardia (80+/-5% of initial at a cumulative dose of 3 mg/kg). At the highest dose, this was characterized by a transient decrease in blood pressure (phase 1) followed by a return to basal level and then a slower decrease in blood pressure (phase 2). Venom also produced a decrease in rate and force of contraction in the rat isolated atria. Interestingly, venom induced a contraction of isolated aortic rings which was blocked by felodipine but not by prazosin, suggesting the contraction is mediated by calcium channel activation. These results suggest that the negative inotropic and chronotropic effects of the venom of N. nomurai may be due to a direct effect on the heart.
Kim
Euikyung
E
Laboratory of Toxicology, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Gajwa-Dong, Jinju 660-701, South Korea. ekim@gnu.ac.kr
Lee
Seunghwan
S
Kim
Jong-Shu
JS
Yoon
Won Duk
WD
Lim
Donghyun
D
Hart
Andrew J
AJ
Hodgson
Wayne C
WC
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003064:Cnidarian Venoms / Q000633:toxicity*; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011674:Pulse; D051381:Rats; D017207:Rats, Sprague-Dawley; D037401:Scyphozoa / Q000472:pathogenicity*; D014661:Vasoconstriction / Q000187:drug effects
D003064:Cnidarian Venoms