title: Occurrence of toxins, other than paralysing type, in the skin of Tetraodontiformes fish.
abstract: Puffer fish (Tetraodontidae and Diodontidae) possess paralysing toxins (tetrodotoxin and analogues) that are secreted upon stimulation. In a previous work it was demonstrated that mucous secretion from the puffer fish Sphoeroides spengleri, when mixed in sea water passing through the orobranchial cavity of groupers, induced cardiorespiratory alterations. In the present study, skin secretions from Ciclichthys spinosus, S. spengleri and Diodon hystrix were tested on crustacean nerves, sea urchin eggs and mouse erythrocyte suspensions to verify neurotoxic and cytotoxic activities. Ciclichthys spinosus and D. hystrix secretions induced transient depolarizations with 0.16 mg and blocked crustacean nerve conduction after prolonged exposure. Both secretions had cytotoxic effects; when applied to sea urchin eggs they caused cleavage inhibition and anomalies in a dose-dependent manner (ED50 +/- S. E. M. = 2.59 +/- 0.08 mg/ml for C. spinosus and 1.23 +/- 0.07 mg/ml for D. hystrix); moreover, hemolysis occurred with an ED50 = 0.76 mg/ml of 0.5% mouse erythrocyte suspensions to C. spinosus and 0.59 mg/ml to D. hystrix. These secretions were not lethal in acute toxicity tests, even at 335 mg/ml. The neurotoxic components were thermolabile while the hemolytic activity was resistant to boiling. Tests with the secretion from S. spengleri did not show cytotoxic effects but promptly blocked action potentials of crustacean nerves and were lethal for mice in acute toxicity rests. When applied to groupers, the C. spinosus secretion caused cardiorespiratory alterations. These results suggest the presence of neurotoxins (other than tetrodotoxin) and cytotoxins in skin of diodontid puffer fish.
authors.affiliation: Department of Physiology, University of Sao Paulo, Brazil.
authors.forename: E L
authors.initials: EL
authors.lastname: Malpezzi
authors.forename: J C
authors.initials: JC
authors.lastname: de Freitas
authors.forename: F T
authors.initials: FT
authors.lastname: Rantin
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity; D003603:Cytotoxins / Q000378:metabolism / Q000633:toxicity; D005071:Evoked Potentials / Q000187:drug effects; D005397:Fish Venoms / Q000378:metabolism* / Q000633:toxicity; D005400:Fishes, Poisonous; D006339:Heart Rate / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D051379:Mice; D009092:Mucous Membrane / Q000737:chemistry / Q000378:metabolism; D009498:Neurotoxins / Q000378:metabolism / Q000633:toxicity; D012119:Respiration / Q000187:drug effects; D012867:Skin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D003603:Cytotoxins; D005397:Fish Venoms; D009498:Neurotoxins