Ts17, a Tityus serrulatus β-toxin structurally related to α-scorpion toxins.

Ts17 was purified from the venom of the scorpion Tityus serrulatus, the most dangerous scorpion species in Brazil. The activity on Na1.1-Na1.

Electrophysiological characterization of Tityus obscurus β toxin 1 (To1) on Na-channel isoforms.

To1, previously named Tc49b, is a peptide neurotoxin isolated from venom of the scorpion Tityus obscurus that is responsible for lethal human poisoning cases in the Brazilian Amazonian region. Previously, To1 was shown to be lethal to mice and to change Na permeation in cerebellum granular neurons from rat brain. In addition, To1 did not affect Shaker B K channels.

Subtype Specificity of β-Toxin Tf1a from in Voltage Gated Sodium Channels.

Scorpion venoms are a complex mixture of components. Among them the most important are peptides, which presents the capacity to interact and modulate several ion channel subtypes, including voltage-gated sodium channels (Na). Screening the activity of scorpion toxins on different subtypes of Na reveals the scope of modulatory activity and, in most cases, low channel selectivity.

To4, the first Tityus obscurus β-toxin fully electrophysiologically characterized on human sodium channel isoforms.

Many scorpion toxins that act on sodium channels (NaScTxs) have been characterized till date. These toxins may act modulating the inactivation or the activation of sodium channels and are named α- or β-types, respectively. Some venom toxins from Tityus obscurus (Buthidae), a scorpion widely distributed in the Brazilian Amazon, have been partially characterized in previous studies; however, little information about their electrophysiological role on sodium ion channels has been published.

Behavioural and neurotoxic effects of ayahuasca infusion (Banisteriopsis caapi and Psychotria viridis) in female Wistar rat.

Ayahuasca, a psychoactive beverage used by indigenous and religious groups, is generally prepared by the coction of Psychotria viridis and Banisteriopsis caapi plants containing N,N-dimethyltryptamine (DMT) and β-carboline alkaloids, respectively. To investigate the acute toxicity of ayahuasca, the infusion was administered by gavage to female Wistar rats at doses of 30X and 50X the dose taken during a religious ritual, and the animals observed for 14 days. Behavioural functions were investigated one hour after dosing at 15X and 30X using the open field, elevated plus maze, and forced swimming tests.

First report of the characterization of the pathophysiological mechanisms caused by the freshwater catfish Pimelodus maculatus (order: Siluriformes).

Injuries caused by aquatic animals in Brazil in most cases are provoked by marine and freshwater catfish. Pimelodus maculatus is a freshwater catfish very common in Brazilian basins that causes frequent accidents mainly amongst fishermen, and whose venom characteristics and pathological mechanisms of the venom are poorly known. In the present study for the first time, we have characterized the main pathophysiological mechanisms associated with the clinical manifestation (pain, local inflammation and edema) of the envenomations caused by P.

Three new species of Proceratophrys Miranda-Ribeiro 1920 from Brazilian Cerrado (Anura, Odontophrynidae).

Based on the analyses of specimens collected at several areas in the Cerrado domain from Central Brazil and others housed in scientific collections and on specimens collected at the type-locality, herein we describe three new species belonging to the P. cristiceps group: Proceratophrys bagnoi sp. nov.