Cardiovascular effects and lethality of venom from nematocysts of the box-jellyfish Chiropsalmus quadrigatus (Habu-kurage) in anaesthetized rats.
Haemodynamic effects of saline-extracted venom from nematocysts isolated from Chiropsalmus quadrigatus (Habu-kurage) were studied in anaesthetized rats. Intravenous administration of venom (0.2-5 microg protein/kg) produced immediately dose-dependent hypertension and bradycardia. Femoral blood flow transiently increased but calculated femoral vascular conductance decreased. Changes caused by 1 microg/kg of venom were reproducible, and were not affected by prazosin, atropine or BQ123 (ET(A) receptor antagonist) but were significantly attenuated by nicardipine. At doses over 2 microg/kg, hypotension and a decrease in pulse pressure were observed subsequent to transient hypertension. In 5 of 8 rats received 5 microg/kg venom and 6 of 6 rats at 10 microg/kg, death due to irreversible cardiac arrest occurred within 30 min after intravenous injection. However, during nicardipine infusion, venom (10 microg/kg) exerted only modest effects and the rats survived. Heating venom (50 degrees C for 10 min) before injection practically abolished the haemodynamic effects of 10 microg/kg venom, indicating its thermolability. Data show that C. quadrigatus venom has both vasoconstrictor and cardiodepressive effects in rats, and suggest that a calcium channel blocker can protect against the cardiovascular and lethal effects of the venom.
Noguchi
Katsuhiko
K
Department of Pharmacology, School of Medicine, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan. noguchi@med.u-ryukyu.ac.jp
Sakanashi
Mayuko
M
Matsuzaki
Toshihiro
T
Nakasone
Junko
J
Sakanashi
Makiko
M
Koyama
Tomoyuki
T
Hamadate
Naobumi
N
Sakanashi
Matao
M
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002319:Cardiovascular System / Q000187:drug effects*; D003064:Cnidarian Venoms / Q000037:antagonists & inhibitors / Q000633:toxicity*; D037462:Cubozoa / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006323:Heart Arrest / Q000139:chemically induced; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009529:Nicardipine / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature
D003064:Cnidarian Venoms; D010456:Peptides, Cyclic; D001285:Atropine; D009529:Nicardipine; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D011224:Prazosin