Koyama Tomoyuki, Noguchi Katsuhiko, Matsuzaki Toshihiro, Sakanashi Mayuko, Nakasone Junko, Miyagi Kanako, Sakanashi Makiko, Sakanashi Matao
Department of Pharmacology, School of Medicine, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa 903-0215, Japan.
Toxicon. 2003 Apr;41(5):621-31. doi: 10.1016/s0041-0101(03)00010-2.
Haemodynamic effects of saline-extracted venom from nematocysts isolated from tentacles of the box-jellyfish Chiropsalmus quadrigatus (Habu-kurage) were investigated. In anaesthetized rabbits, i.v. injections of the venom produced hypotension following a transient hypertension. Mean femoral arterial blood flow markedly decreased immediately after the injection and femoral vascular resistance increased. Left ventricular dP/dt remarkably decreased after a transient and small increase, and heart rate decreased. Left ventricular end-diastolic pressure markedly elevated. All of the above changes by 0.2-5 microg/kg of the venom expressed as the amount of protein were seen dose-dependently and occurred without tachyphylaxis. In five of seven animals received an injection of the venom at 10 microg/kg, irreversible cardiac arrest occurred. Changes produced by 1 or 2 microg/kg of the venom were significantly attenuated either by heating the venom at 40 degrees C for 10min or by pretreatment with diltiazem. These results indicate that the venom from Habu-kurage has both vasoconstrictor and cardiodepressive effects, and suggest that these thermolabile actions may be due partly to activation of voltage-dependent calcium channels and probably subsequent calcium-overload.
