Geraldine J. Fuhrman

The occurrence of tetrodotoxin (tarichatoxin) in amphibia and the distribution of the toxin in the organs of newts (Taricha)

Abstract Among amphibia tetrodotoxin was found by bioassay only in the family Salamandridae. It was present in substantial concentration (mean value of about 25 μg per g) only in the genus Taricha: T. torosa, T. rivularis, T. granulosa; smaller amounts (1–4 μg per g) were found in Notophthalmus viridescens, Cynops pyrrhogaster, C. ensicauda and trace amounts (less than 0·1 μg per g) in Triturus vulgaris, T. cristatus, T. alpestris, T. marmoratus. This toxin was not detected in fourteen species of the orders Caudata and Salientia. In adult Taricha torosa, tetrodotoxin is concentrated in the skin, ovaries and ova, muscle and blood and is present in trace amounts in the liver, viscera and testes

Toxin from Skin of Frogs of the Genus Atelopus: Differentiation from Dendrobatid Toxins

A potent, dialyzable toxin (atelopidtoxin) occurs in the skin of frogs of the genus Atelopus. A concentrate of atelopidtoxin from Atelopus zeteki has an LD50 in mice of 16 micrograms per kilogram. It differs from batrachotoxin, tetrodotoxin, and saxitoxin, the only known nonprotein substances of greater toxicity, as well as from all toxins previously isolated from amphibia.

Chemistry and pharmacology of skin toxins from the frog Atelopus zeteki (atelopidtoxin: zetekitoxin).

Abstract Chemistry and pharmacology of skin toxins from the frog Atelopus zeteki (atelopidtoxin; zetekitoxin). Toxicon 15, 115–128, 1977.—Zetekitoxins were obtained in purified form from skins of the Panamanian frog Atelopus zeteki by a series of steps which used preparative free-flowing electrophoresis in the last stages. The minor, less toxic component (zetekitoxin C) had an ld 50 of 80 μg per kg (i.p., mouse), and the major, more toxic component (zetekitoxin AB) had an ld 50 of 11 μg per kg. These toxins are water-soluble, low molecular weight, non-polypeptide, non-steroid and non-carbohydrate in nature. The zetekitoxins are clearly different from tetrodotoxin and chiriquitoxin. Atelopus zeteki were resistant to toxin obtained from their own skins. Zetekitoxin AB (1·5–3 μg per kg) produced sustained hypotension in anesthetized dogs and cats, during which time the pressor response to epinephrine and norepinephrine was unchanged, but that to carotid occlusion was reduced. The toxin at a concentration of 0·5 μg per 1 blocked vasoconstriction caused by electrical stimulation of perfused rabbit ear arteries, and this effect was antagonized by dextroamphetamine. It did not reduce contraction of the nicitating membrane or block α-adrenergic receptors (vas deferens). It partially blocked β-adrenergic receptors (guinea pig atria) only in high concentrations above 10 μg per 1.

Isolation of allantoin and adenosine from the marine sponge Tethya aurantia

Abstract 1. 1. Propanol extracts of the sponge Tethya aurantia (Demospongiae) were fractionated, guided by bioassay, for a component with negative chronotropic and inotropic activity on isolated guinea pig atria. 2. 2. The bioactive component was found to be adenosine. These extracts also contained allantoin. 3. 3. This intermediate in the sequence of degradation of purines was unexpected, since it has been reported only once before to occur in marine invertebrate animals.

Toxic effects produced by extracts of eggs of the cabezon Scorpaenichthys marmoratus

The eggs of the cabezon Scorpaenichthys marmoratus, a cottid fish found in the shallow waters off the coast of western North America, contain a toxin that is non-dialyzable and thermolabile. Crude preparations of the toxin inhibit growth of mouse L-cell fibroblasts in tissue culture. In spite of some superficial resemblances to α-amanitin, the toxin from cabezon roe failed to significantly alter the nuclear RNA/DNA ratio in the liver. After i.p. injection of the toxin into mice, the total number of white cells in peripheral blood increases, but the absolute number and percentage of lymphocytes decrease significantly.