The understanding of the molecular basis of the envenomation processes caused by venoms from arthropods such as spiders, scorpions, caterpillars and bees are important for the diagnosis and treatment of the clinical profile. Furthermore, identification and characterization of the active principles that compose venoms are of great

interest for the development of new drugs capable of directly and specifically act upon cell physiology. Table 1 summarizes the main molecules studied in these venoms. As mentioned above, animal venoms are composed of a variety of active principles, which Angiogenesis inhibitor may cause different effects on cell physiology, depending on the cell type and momentum (i.e., which receptors, signiling peptides and other molecules are being expressed in the cell). Thus, it is important to identify the main venom components and their specific targets in the studied cells in order to find candidates for clinical

trials aiming their application in the treatment of diseases. With the improvement of molecular biology techniques it is possible to produce recombinant toxins in large scale, and use them to design new drugs for industrial application or directly for therapeutic use (Banerjee et al., Hormones antagonist 2004). The clinical application of these toxins has been apparent for some diseases such as hypertension and thrombosis; regarding the treatment of cancer, the first promising results are beginning to emerge. T. E. Heinen is sponsored by a graduate student fellowship from the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) of the Ministry of Education (MEC), Federative Republic of Brazil. “
“Sphingomyelin

(SM) is the generic name for N-acyl-sphingosine-1-phosphorylcholine (Ramstedt and Slotte, 2002) and is an important component of the plasma membranes of eukaryotic cells (Koval and Pagano, 1991). SM functions as a structural component in biological Dapagliflozin membranes together with other phospholipids, glycolipids, cholesterol (CH) and some integral membrane proteins. Products of SM metabolism, like ceramide, sphingosine and sphingosine-1-phosphate, are important cellular effectors and give SM a role in cellular functions like apoptosis, aging and development (Hannun et al., 2001). Sphingomyelinase-D (SMase-D) or sphingomyelin phosphodiesterase D (EC number 3.1.4.41) catalyzes the hydrolysis of sphingomyelin resulting in the formation of ceramide 1-phosphate (C1P) and choline or the hydrolysis of lysophosphatidyl choline, generating the lipid mediator lysophosphatidic acid (LPA) (van Meeteren et al., 2004). C1P is implicated in the stimulation of cell proliferation via a pathway that involves inhibition of acid sphingomyelinase and the simultaneous blocking of ceramide synthesis (Gómez-Muñoz, 2004).