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Cupo, P., Azevedo-Marques, M.M., Hering, S. (2003). Escorpionismo. In: Cardoso, J.L.C., Fran?a, F.O.S., Wen, F.H., Málaque, C.M.S., Haddad Jr, V., Eds., Animais Pe?onhentos do Brasil: Biologia, Clínica e Terapêutica dos Acidentes, Sarvier, S?o Paulo, 198-208.

has been cited by the following article:

• TITLE: Tityus serrulatus venom and its toxins Ts1 and Ts5 increase cytosolic Ca2+ concentration in isolated vascular smooth muscle cells

  AUTHORS: Mário dos A. Neto, Flávio Vasconcelos, Lusiane M. Bendhack, Eliane C. Arantes

  KEYWORDS: Ts1; Ts5; Na+ Channel; Ca2+ Channel; Tityus serrulatus

  JOURNAL NAME: Journal of Biophysical Chemistry, Vol.3 No.4, November 29, 2012

  ABSTRACT: Voltage-gated Na+ channel (Nav channel) scorpion toxins are classified as α- and β-neurotoxins. Ts5 (α-neurotoxin) and Ts1 (β-neurotoxin) from Tityus serrulatus venom (TsV) interact with Nav channels, increasing Na+ influx and activating voltage-dependent Ca2+ channels. This study aimed to investigate the effect of TsV, Ts1 and Ts5 on the cytosolic Ca2+ concentration ([Ca2+]C) in rat aortic smooth muscle cells. Toxins were isolated by ion exchange chromatography (Ts1) followed by RP-HPLC (Ts5). The rat aortic smooth muscle cells were isolated in Hanks buffer pH 7.4 and loaded with 5 μmol/L of Fura-2AM (45 minutes at 37℃), in order to measure [Ca2+]C by fluorescence of Fura-2/AM (ratio 340/380 nm). The fluorescence was measured in one single cell (excitation: 340 and 380 nm; emission: 510 nm). TsV (100 and 500 mg/mL) and its toxins Ts1 and Ts5 (50 and 100 mg/mL each) led to a concentration-dependent increase in [Ca2+]C. Tetrodotoxin (1 mmol/L), a Nav channel blocker, and verapamil (1 mmol/L), a voltage-operated Ca2+ channel blocker, inhibited the increase in [Ca2+]C induced by TsV (500 mg/mL). In conclusion, TsV and its toxins induce a concentration-dependent increase in [Ca2+]C that probably occurs through interaction with Nav channels, thus inducing depolarization and consequent Ca2+ influx. This assumption is based on the fact that this effect is inhibited by tetrodotoxin and verapamil, showing a direct action of TsV toxins on aorta smooth muscle cells.