Cellular and Molecular Neurobiology, Vol. 22, Nos. 5/6, December 2002 ( C  2002) Review Phoneutria nigriventer Venom: A Cocktail of Toxins That Affect Ion Channels Marcus V. Gomez, 1,3 Evanguedes Kalapothakis, 1 Cristina Guatimosim, 1,2 and Marco A. M. Prado 1 Received August 26, 2002; accepted September 10, 2002 SUMMARY 1. We review the pharmacological actions of toxins present in the venom of the aggres- sive spider Phoneutria nigriventer. 2. This venom is rich in toxins that affect ion channels and neurotransmitter release. Voltage-gated sodium, calcium, and potassium channels have been described as the main targets of these toxins. 3. In addition to these classical actions Phoneutria toxins have also been shown to affect glutamate transporter. 4. It is expected that molecular genetics in addition to biochemical, biophysical and pharmacological approaches will help to further define Phoneutria toxins and their mecha- nisms of action in the near future. KEY WORDS: Phoneutria nigriventer; toxins; ion channels; calcium channels; sodium chan- nels; glutamate transport. Poisonous animals have developed effective strategies to paralyze and/or kill preys that make them very successful hunters and fearless defenders against larger preda- tors. Although several chemical defenses may be used, proteins and peptides are a common component of most venoms. Some venoms present large amounts of dis- tinct peptide toxins, and thus these organisms are likely to use elegant genetic and biochemical strategies to generate the toxins. Although this could be considered a 1 Departamento de Farmacologia, Instituto de Ciˆ encias Biol ´ ogicas Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil. 2 Departamento de Morfologia, Instituto de Ci ˆ encias Biol ´ ogicas Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil. 3 To whom correspondence should be addressed at Departamento de Farmacologia, Instituto de Ciˆ encias Biol ´ ogicas Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627 Belo Horizonte, MG, Brasil 31270-901; e-mail: gomez@icb.ufmg.br. 579 0272-4340/02/1200-0579/0 C  2002 Plenum Publishing Corporation