STRUCTURAL AND ULTRASTRUCTURAL CHARACTERIZATION OF THE VENOM GLAND OF Vitalius dubius (ARANEAE, THERAPHOSIDAE)

ROCHA E SILVA T.A.A. (1), CRUZ-HÖFLING M.A. (2), COLLARES-BUZATO C.B. (2), HYSLOP S. (1)

(1) Dept. of Pharmacolgy, Faculty of Medical Sciences and (2) Dept. of Histology and Embryology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil.

Tarantulas (family Theraphosidae) produce venom to subdue prey and for defense. We have previously described the general organization and histology of the venom apparatus of Vitalius dubius, a tarantula species found in southeastern Brazil [1]. In this work, we provide additional findings on the organization and ultrastructure of this venom gland. Histologically, the venom gland consisted of an external layer of striated muscle lined internally and externally by an elastin-rich basal membrane that supported the secretory epithelium. The venom-producing epithelium formed a complex network of anastomosing nuclei adjacent to the basal layer and long cytoplasmic elongations that extended into the lumen to form large venom-containing vesicles. Fluorescence confocal microscopy revealed abundant filamentous actin that contributed to the epithelial organization and shape. Transmission electron microscopy showed abundant smooth and rough endoplasmic reticulum, Golgi complexes and mitochondria. Ultrastructurally, glands 1, 3, 7 and 15 days after venom milking showed epithelial changes that included a looser nuclear organization, alterations in the abundance of endoplasmic reticulum and Golgi apparatus, and the formation of venom-containing vesicles.  

KEY WORDS: tarantula, regeneration, ultrastructure, venom gland.

REFERENCES: 1. ROCHA E SILVA T.A.A., CRUZ-HÖFLING M.A., HYSLOP S. Structural organization of the chelicerae and venom gland of Vitalius dubius (Araneae, Theraphosidae). In: VIII Congresso da Sociedade Brasileira de Toxinologia/VIII Symposium of the Pan American Section of the International Society on Toxinology, September 2004, Angra dos Reis, RJ, Brazil. p. 163.

FINANCIAL SUPPORT: FAPESP.

CORRESPONDENCE TO: THOMAZ A. A. ROCHA E SILVA. Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), PO Box 6111, 13083-970, Campinas, SP, Brazil. Tel.: +55-19-3521-9535, Fax: +55-19-3788-9536, E-mail: taars@unicamp.br; hyslop@fcm.unicamp.br