[3H]Saxitoxin binds to a single class of receptor sites in rat brain synaptosomes and in broken membrane fractions derived from rat brain with a KD of approximately 2 11~ at 36°C. Batrachotoxin and scorpion toxin, which act at different receptor sites to activate sodium channels, have no effect on saxitoxin binding. Osmotic lysis and depolarization also have no effect on saxitoxin binding. Thes...

Sodium currents mediated by voltage-sensitive sodium channels in normal and scorpion toxin-resistant neuroblastoma cells were measured using a giga-ohm seal recording method in the whole cell patch configuration. The voltage and time dependence of sodium currents were similar in normal and mutant cell lines. Half-maximal activation occurred for test depolarizations in the range of -7 to -11 mV....

Although many studies concerning the sensitivity mechanism of scorpion toxin-potassium channel interactions have been reported, few have explored the biochemical insensitivity mechanisms of potassium channel receptors toward natural scorpion toxin peptides, such as the KCNQ1 channel. Here, by sequence alignment analyses of the human KCNQ1 channel and scorpion potassium channel MmKv2, which is c...

Voltage sensing by voltage-gated sodium channels determines the electrical excitability of cells, but the molecular mechanism is unknown. ß-scorpion toxins bind specifically to neurotoxin receptor site 4 and induce a negative shift in the voltage dependence of activation through a voltagesensor trapping mechanism. Kinetic analysis showed that β-scorpion toxin binds to the resting state and subs...

introduction: scorpion venoms contain a variety of peptides, toxic to mammals، insects and crustaceans and are the main factors in scorpion venom toxicity (their amount being 1-3% of total venom). most of the scorpion toxins have been isolated from the venoms of scorpions in the buthidae family. the scorpion buthotus schach of this family is widely found in the western regions of iran, but no p...

The action of neurotoxins on tetrodotoxin-insensitive sodium channels in cultured rat muscle cells has been studied by ion flux methods. The alkaloid neurotoxins batrachotoxin, veratridine, and aconitine act at a common receptor site to cause persistent activation of sodium channels. Batrachotoxin is a full agonist, while veratridine and aconitine are partial agonists activating 8% and 1% of so...

BACKGROUND Recently, a new subfamily of long-chain toxins with a Kunitz-type fold was found in scorpion venom glands. Functionally, these toxins inhibit protease activity and block potassium channels. However, the genomic organization and three-dimensional (3-D) structure of this kind of scorpion toxin has not been reported. PRINCIPAL FINDINGS Here, we characterized the genomic organization a...

PURPOSE: Scorpion toxin purified from Tityus serrulatus venom (Tx) induces an increase in volume, acidity and pepsin secretion in the gastric juice of rats. Ligation of oesophagus has been shown to reduce the acid gastric secretion in rats. The aim of this paper was to determine the influence of the esophageal ligation on gastric secretion induced by Tx in rats METHODS: Forty-four male albino r...

Intravenous injection of scorpion toxin (Tityus serrulatus) in normal and Trypanosoma cruzi infected rats did not cause ultrastructural morphologic changes on enterochromaffin-like (ECL) cells of the stomach, although it induced a significant increase of the gastric secretion. Our data seem to indicate that gastric ECL cells structure is not affected by stimulation with scorpion toxin or by acu...

beta-Scorpion toxins shift the voltage dependence of activation of sodium channels to more negative membrane potentials, but only after a strong depolarizing prepulse to fully activate the channels. Their receptor site includes the S3-S4 loop at the extracellular end of the S4 voltage sensor in domain II of the alpha subunit. Here, we probe the role of gating charges in the IIS4 segment in beta...