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Poster 147. Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil. Abstracts... J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.506. |
Occurrence Of Indolealkylamines In The Skin Secretions Of Two Frogs: Melanophryniscus cambaraensis (Bufonidae) And Leptodactylus syphax (Leptodactylidae).
1Dourado, F.S.; Maciel, N.M.; Tollendal, F.; Schwartz, C.A. and Schwartz, E.F.
1 Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília-DF.
The cutaneous secretions of amphibians are a rich source of active compounds including peptides, proteins, alkaloids, steroids and biogenic amines. The function of these compounds may involve defense against predators and microorganisms because of their pharmacological activity. Indolealkylamines are by far the most important and abundant biogenic amines found in amphibian skin. In the past 30 years many pharmacological properties have been described to these molecules including hallucinogenic and convulsant effects. Beyond their pharmacological interest, the indolealkylamines should be considered as a subsidiary tool in biochemical taxonomy and for assessing evolutionary relationships. In the present study we describe the occurrence of indolelakylamines in the skin secretion of two Brazilian frogs, Melanophryniscuscambaraensis (Bufonidae) and Leptodactylussyphax (Leptodactylidae). The skin secretions were obtained by mild electric stimulation. The secretion was dried and submitted to thin-layer chromatography (Silica gel H plates 10X20cm) using a mixture of ethyl acetate, isopropylic acid and ammonium hydroxide (25%) (9:7:4, v:v:v) as eluent. The amines were revealed with ophthalaldehyde (OPT) and Gibbs reagents. The visualization of the spots by OPT was done under UV light (375 nm). The qualitative indolealkylamines analyses were made by the respective Rf, determined by the distance (cm) ran by the amine divided by the distance (cm) ran by the solvent front. The skin secretion of Melanophryniscuscambaraensis showed a great amount of bufotenin (BTN) beyond other five amines. Leptodactylussyphax skin secretion has serotonin (5-HT), bufotenidin (BTD) and other two amines. Additional experiments, including mass spectrometry, are in progress to elucidate the indolealkylamines not known.
Correspondence to: fsdourado@unb.br