Frog secretions and hunting magic in the upper Amazon: identification of a peptide that interacts with an adenosine receptor.

Abstract

A frog used for "hunting magic" by several groups of Panoan-speaking Indians in the borderline between Brazil and Peru is identified as PhyUomedusa bicolor. This frog's skin secretion, which the Indians introduce into the body through fresh burns, is rich in peptides. These include vasoactive peptides, opioid peptides, and a peptide that we have named adenoregulin, with the sequence GLWSKIKE-VGKEAAKAAAKAAGKAALGAVSEAV as determined from mass spectrometry and Edman degradation. The natural peptide may contain a D amino acid residue, since it is not identical in chromatographic properties to the synthetic peptide. Adenoregulin enhances binding of agonists to Al adenosine receptors; it is accompanied in the skin secretion by peptides that inhibit binding. The vasoactive peptide sauvagine, the opioid peptides, and adenoregulin and related peptides affect behavior in mice and presumably contribute to the behavioral sequelae observed in humans. We here identify the frog used by the Peruvian Matses and Brazilian Mayoruna Indians as Phyllomedusa bicolor (Boddaert), a large green hylid that inhabits lowland rain forest throughout much of the Amazon basin and the Guayanan region (Fig. 1 Upper). Skin extracts from this species have been previously studied and are known to contain a variety of vasoactive peptides (4). These include high levels of phyllocaerulein, phyllokinin, and phyllomedusin and moderate levels of sauvagine. Small amounts of deltorphins, a class of opioid agonists selective for 8 receptors, also are present (5). We initially felt it unlikely that either the vasoactive peptides or the small amounts of deltorphins would account for effects on humans attributed to secretions from P. bicolor. Therefore, an examination was initiated of the effects of extracts of dried secretion from a Mayoruna frog stick.EXPERIMENTAL PROCEDURES AND RESULTS Extraction and Behavioral Effects. A stick holding dried skin secretion from P. bicolor was acquired by K.M. at the Rio Lobo site in western Brazil. The Rio Lobo stick was scraped to provide 400 mg of dried frog secretion, which was triturated first with 6 ml of methanol to yield a pale yellow methanol extract and then with 6 ml of water to yield a pale yellow aqueous extract. Extracts were stored at -20'C. Subcutaneous injection into mice of methanol and aqueous extracts in doses equivalent to 0.1-6 mg of dried secretion resulted in a dose-dependent reduction in spontaneous locomotor activity. At higher doses mice were completely inactive for several hours, although when touched they would respond briefly and then reassume a lethargic state. The aqueous extract produced a less active state at a threshold dose equivalent to 0.1 mg of dried secretion, whereas the methanol extract required a dose of 0. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

The chains of the heterodimeric amphibian skin antimicrobial peptide, distinctin, are encoded by separate messenger RNAs

“…Amphibians are known to release bioactive compounds from their skin granular glands that include alkaloids, steroids, biogenic amines, proteins and peptides [1,2]. Many hundreds of different peptides, differing in size, charge, hydrophobicity, conformation, primary structure, as well as in post-translational modifications, have been demonstrated in frog defensive skin secretions.…”

Dermaseptins from Phyllomedusa oreades andPhyllomedusa distincta

“…The capacity of the dermaseptins to discriminate between mammalian and microbial cells has been known for more than a decade (13,14), and it is mainly due to the amino acid composition of the peptides and to the differences encountered in the physical-chemical properties of membranes (13)(14)(15)(16)(17)(18)(19)(20). Besides the phospholipid content, the cell lysis mediated by amphiphilic antimicrobial peptides such as the dermaseptins is attenuated by increasing amounts of membrane cholesterol (21,22).…”

Utilização medicinal da secreção (“vacina-do-sapo”) do anfíbio kambô (Phyllomedusa bicolor) (Anura: Hylidae) por população não-indígena em Espigão do Oeste, Rondônia, Brasil

“…A utilização das secreções dos anfíbios por populações indígenas foi registrada em algumas localidades amazônicas (Myers et al, 1978;Daly et al, 1992). Na região de Chocó (Colômbia), índios utilizam o veneno de Phyllobates terribilis (Dendrobatidae) para envenenar as pontas de dardos para serem lançados em zarabatanas durante caçadas (Myers et al, 1978).…”

“…Na região de Chocó (Colômbia), índios utilizam o veneno de Phyllobates terribilis (Dendrobatidae) para envenenar as pontas de dardos para serem lançados em zarabatanas durante caçadas (Myers et al, 1978). Algumas tribos indígenas na Amazônia utilizam as secreções de Phyllomedusa (Hylidae) para fins medicinais (Daly et al, 1992;Caramaschi e Cruz, 2002;Souza et al, 2002). Os Ticunas a usam na preparação do "curare" (Caramaschi e Cruz, 2002).…”