EVALUATION OF THE GLANDULAR DISTRIBUTION OF A HIGHLY TOXIC PROTEIC FRACTION FROM Leptodactylus pentadactylus SKIN SECRETION, IN THE GRANULAR CUTANEOUS GLANDS OF ANURA

HONÓRIO JR J.E.R. (1,2), SOUZA NETO J.A. (1), FONTENELE-BERTO, R. (2), CORDEIRO-SOUSA, J. (2), OLIVEIRA R.G.S. (1), CARVALHO K.M. (1), CARDI B.A. (1,2)

(1) Laboratório de Toxinologia e Neurofarmacologia Molecular, ISCB/UECE/Brazil, (2) Laboratório de Animais Peçonhentos (LAPE), ISCB/UECE/Brazil

Leptodactylus pentadactylus skin secretion is very rich on bioactive compounds. Our group had been purified a highly toxic proteic fraction (LP8) from this secretion and pharmacological assays (rats, i.v.) showed that it induces an acute decrease of the blood pressure, together with a inotropic positive effect upon heart, but without interfering on the heart frequency rate. Here we report a imounohystochemical investigation about glandular location of probable storage site of LP8 or precursor molecules, using polyclonal mouse IgG anti-LP8 antibody. Thus specific antibodies were assayed with 7 µm slices of dorsal skin of some anura, such as Bufo jimmi, Scinax sp. and L. pentadactylus, previously processed by hystological routine, after Boiun fixation. Reaction was started, first by incubation the slides with goat IgG anti-mice IgG linked to peroxidase, following by incubation with 3,3’-diaminobenzidine-hydrogen peroxide solution. We just found positive reaction on L. pentadactylus glandular tissue. In these preparations, positive reactions were observed on secretory granules located on pericentral zone of serous cutaneous glands, being absence on peripheral synthesis zone of these glands. Glands that released all their secretory products not presented any immunoreation. Discrete immunoreaction were observe near the secretory-contractile interface. Based on these results, we suggested that LP8 originates as a large proteic precursor, being storage on mature secretory granules after maturational processes, migrating to central alveolar zone of serous gland after process, in order to be ready to secretion events. The absence of immunoreaction on the other preparations of anuran skin lead us to believe that this toxin is a specific compound of L. pentadactylus serous gland secretion.

KEY WORDS: immunohistochemistry, Leptodactylus pentadactylus, anuran serous cutaneous gland

FINANCIAL SUPPORT: FUNCAP, CNPq, PRONEX

CORRESPONDENCE TO: Bruno A Cardi, Email: bcarditoxinol@gmail.com