Potassium Channel Toxins

Calcium-Activated Potassium Conductances in Retinal Ganglion Cells of the Ferret

“…After disso-The BK Ca channels can be blocked by charybdotoxin, have ciation, the cell suspension was immediately sieved through a nylon a high unitary conductance, and display sensitivity to both mesh (Tetko Nitex 3-250/50) to remove cell clots and tissue debris. The retinal cells were then plated onto coated coverslips and voltage and submicromolar concentrations of charybdotoxin affecting other types of K / conductances (Meves 1992; Pineda et stored in a humidified incubator (5% CO 2 ; 36.5ЊC) until ready for al. 1992).…”

Induction by β‐bungarotoxin of apoptosis in cultured hippocampal neurons is mediated by Ca2+‐dependent formation of reactive oxygen species

“…2001), a non‐phospholipase ligand of voltage‐activated K + channels that exerts effects resembling the short‐term mode of action of β‐BuTx (Dolly 1992). Indeed, both toxins compete for the same class of membrane surface receptors (Rehm and Lazdunski 1988; Meves 1992). The subsequent events, however, relating the initial receptor binding of β‐BuTx to the final stage of cell death, are not understood.…”

“…b-bungarotoxin induction of neuronal cell death by ROS 605 DNA fragmentation, chromatin condensation and the formation of pycnotic nuclei, b-BuTx is an extremely potent inducer of apoptosis in cultured neurons, yielding EC 50 values in the range of 5 · 10 )13 M. Induction of neuronal apoptosis is antagonized by dendrotoxin I ), a non-phospholipase ligand of voltage-activated K + channels that exerts effects resembling the short-term mode of action of b-BuTx (Dolly 1992). Indeed, both toxins compete for the same class of membrane surface receptors (Rehm and Lazdunski 1988;Meves 1992). The subsequent events, however, relating the initial receptor binding of b-BuTx to the final stage of cell death, are not understood.…”

Neurotoxic Effects of Three Fractions Isolated from Tityus serrulatus Scorpion Venom

“…Neurotoxins are present in the venom of most scorpions and some of them are responsible for the effects observed during envenomation. These neurotoxins can act on sodium and potassium channels (Couraud & Jover 1983;Becker & Gordon 1992;Meves 1992). Tityus serrulatus venom and its toxins release acetylcholine from rat brain (Gomez & Farrel 1985;Prado et al 1990), glutamate, aspartate and GABA in vivo and in vitro from rat cerebral cortex (Coutinho-Neto et al 1980), and increase the release of 3 H-noradrenaline induced by potassium in slices of rat brain cortex and hypothalamus (Adler-Graschinsky & Langer 1978).…”