Cardiovascular actions of the venom from the Irukandji (Carukia barnesi) jellyfish: effects in human, rat and guinea-pig tissues in vitro and in pigs in vivo
Winkel, Kenneth D., Tibballs, James, Molenaar, Peter, Lambert, Gavin, Coles, Peter, Ross-Smith, Mark, Wiltshire, Carolyn, Fenner, Peter J., Gershwin, Lisa-Ann, Hawdon, Gabrielle M., Wright, Christine E., and Angus, James A. (2005) Cardiovascular actions of the venom from the Irukandji (Carukia barnesi) jellyfish: effects in human, rat and guinea-pig tissues in vitro and in pigs in vivo. Clinical and Experimental Pharmacology and Physiology, 32 (9). pp. 777-788.
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1. We have investigated the cardiovascular pharmacology of the crude venom extract (CVE) from the potentially lethal, very small carybdeid jellyfish Carukia barnesi, in rat, guinea-pig and human isolated tissues and anaesthetized piglets. 2. In rat and guinea-pig isolated right atria, CVE (0.1-10 μg/mL) caused tachycardia in the presence of atropine (1 μmol/L), a response almost completely abolished by pretreatment with tetrodotoxin (TTX; 0.1 μmol/L). In paced left atria from guinea-pig or rat, CVE (0.1-3 μg/mL) caused a positive inotropic response in the presence of atropine (1 μmol/L). 3. In rat mesenteric small arteries, CVE (0.1-30 μg/mL) caused concentration-dependent contractions that were unaffected by 0.1 μmol/L TTX, 0.3 μmol/L prazosin or 0.1 μmol/L ω-conotoxin GVIA. 4. Neither the rat right atria tachycardic response nor the contraction of rat mesenteric arteries to CVE were affected by the presence of box jellyfish (Chironex fleckeri) antivenom (92.6 units/mL). 5. In human isolated driven right atrial trabeculae muscle strips, CVE (10 μg/mL) tended to cause an initial fall, followed by a more sustained increase, in contractile force. In the presence of atropine (1 μmol/L), CVE only caused a positive inotropic response. In separate experiments in the presence of propranolol (0.2 μmol/L), the negative inotropic effect of CVE was enhanced, whereas the positive inotropic response was markedly decreased. 6. In anaesthetized piglets, CVE (67 μg/kg, i.v.) caused sustained tachycardia and systemic and pulmonary hypertension. Venous blood samples demonstrated a marked elevation in circulating levels of noradrenaline and adrenaline. 7. We conclude that C. barnesi venom may contain a neural sodium channel activator (blocked by TTX) that, in isolated atrial tissue (and in vivo), causes the release of transmitter (and circulating) catecholamines. The venom may also contain a 'direct' vasoconstrictor component. These observations explain, at least in part, the clinical features of the potentially deadly Irukandji syndrome.
|Item Type:||Article (Refereed Research - C1)|
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|FoR Codes:||06 BIOLOGICAL SCIENCES > 0602 Ecology > 060299 Ecology not elsewhere classified @ 100%|
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%|
|Deposited On:||02 Dec 2010 12:33|
|Last Modified:||15 May 2013 01:19|
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