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Tx2-6 is a toxin found in the venom of the Brazilian wandering spider, Phoneutria nigriventer (Keyserling). It is a peptide of 48 residues, molecular weight 5291.3.[1] This peptide is cleaved from a longer precursor with a signal peptide and a glutamine-rich propeptide. It can cause priapism. Tests on rats indicate that the toxin causes nitric oxide release, and its effect on erection is blocked by the nitric oxide synthase inhibitor L-NAME. However, it fully restored erectile function in rats developing hypertension due to injection of deoxycorticosterone acetate.[2] A study is underway at the Medical College of Georgia looking at possible uses for the chemical in erectile dysfunction medication.[3]

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  1. ^ Cordeiro Mdo N, Diniz CR, Valentim Ado C, von Eickstedt VR, Gilroy J, Richardson M (September 1992). "The purification and amino acid sequences of four Tx2 neurotoxins from the venom of the Brazilian 'armed' spider Phoneutria nigriventer (Keys)". FEBS Lett. 310 (2): 153–6. doi:10.1016/0014-5793(92)81318-G. PMID 1397265. 
  2. ^ Nunes, Kenia P.; et al. (2008). "Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function". Toxicon. 51 (7): 1197–1206. doi:10.1016/j.toxicon.2008.02.010. PMC 3019117Freely accessible. PMID 18397797. 
  3. ^ Hernandez, Vladimir (4 May 2007). "Spider venom could boost sex life". BBC News. 

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