Biomaterial Database

Mode of action of ciguatoxin from the Spanish Mackerel, Scomberomorus commersoni, on the guinea-pig ileum and vas deferens. 1984

R J Lewis, and R Endean

Ciguatoxin causes a sustained contraction of the guinea-pig ileum at all doses tested. The contraction was dose dependent and at a high dose of 0.25 mouse units/ml the contraction lasted for approximately 24 min. Associated with this sustained contraction were bursts of contractile activity. The ileum was refractory to repeated doses of ciguatoxin. The response to ciguatoxin was completely blocked by atropine, tetrodotoxin and low Na+ Ringer but was unaffected by hexamethonium or mepyramine. Ciguatoxin did not alter ileal responses to histamine, acetylcholine and 5-hydroxytryptamine. The ileal response to nicotine was, however, irreversibly reduced by prior exposure to ciguatoxin. Eserine potentiated the ileal response to ciguatoxin. It is proposed that the contractile action of ciguatoxin on the guinea-pig ileum is the result of a release of acetylcholine from cholinergic nerve terminals. This release is via nerve excitation produced by a Na+-dependent depolarization of postganglionic neural elements. The tachyphylactic nature of the action of ciguatoxin indicates that nerve stimulation is followed by nerve blockade, probably as the result of further nerve depolarization caused by ciguatoxin. The action of ciguatoxin isolated here is not different from the action of ciguatoxin isolated from moray eel viscera when tested on guinea-pig vas deferens. Ciguatoxin has a similar indirect action on the ileum and vas deferens. The action of ciguatoxin is compared with the action of other marine toxins on the guinea-pig ileum and vas deferens, particularly okadaick acid, a toxin chemically similar to ciguatoxin.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D008297	Male		Males
D008387	Marine Toxins	Toxic or poisonous substances elaborated by marine flora or fauna. They include also specific, characterized poisons or toxins for which there is no more specific heading, like those from poisonous FISHES.	Marine Biotoxins,Phycotoxins
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D002922	Ciguatoxins	Polycyclic ethers produced by Gambierdiscus (DINOFLAGELLATES) from gambiertoxins, which are ingested by fish which in turn may be ingested by humans who are susceptible to the CIGUATERA POISONING.	Ciguatoxin
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001285	Atropine	An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.	AtroPen,Atropin Augenöl,Atropine Sulfate,Atropine Sulfate Anhydrous,Atropinol,Anhydrous, Atropine Sulfate,Augenöl, Atropin,Sulfate Anhydrous, Atropine,Sulfate, Atropine