title: Phoneutria nigriventer toxins block tityustoxin-induced calcium influx in synaptosomes.
abstract: Neurotoxins can help the understanding of mechanisms involved in neurotransmission. We here report that two neurotoxin isoforms, Tx3-3 and Tx3-4 obtained from the venom of the spider Phoneutria nigriventer inhibited the 45Ca2+ influx in rat cortical synaptosomes induced by the scorpion venom tityustoxin. The IC50 for Tx3-3 and Tx3-4 were 0.32 and 7.9 nM, respectively. The neurotoxins Tx3-3 and Tx3-4 are very effective in inhibiting 45Ca2+ influx and they should be useful in studies involving Ca(2+)-dependent processes.
authors.affiliation: Departmento de Farmacologia, ICB-UFMG, Belo Horizonte-MG, Brasil.
authors.forename: D M
authors.initials: DM
authors.lastname: Miranda
authors.forename: M A
authors.initials: MA
authors.lastname: Romano-Silva
authors.forename: E
authors.initials: E
authors.lastname: Kalapothakis
authors.forename: C R
authors.initials: CR
authors.lastname: Diniz
authors.forename: M N
authors.initials: MN
authors.lastname: Cordeiro
authors.forename: T M
authors.initials: TM
authors.lastname: Santos
authors.forename: M A
authors.initials: MA
authors.lastname: Prado
authors.forename: M V
authors.initials: MV
authors.lastname: Gomez
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002540:Cerebral Cortex / Q000378:metabolism*; D007700:Kinetics; D009479:Neuropeptides / Q000494:pharmacology*; D009498:Neurotoxins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012604:Scorpion Venoms / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013111:Spider Venoms / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002132:Calcium Radioisotopes; D009479:Neuropeptides; D009498:Neurotoxins; D012604:Scorpion Venoms; D013111:Spider Venoms; C098736:Tx3 neurotoxin; C003609:tityustoxin; D002118:Calcium