Add time:07/16/2019         Source:sciencedirect.com

The effects of synthetic ω-grammotoxin SIA (ra-GsTx SIA) and synthetic ω-Aga-IVA were tested in in vitro and in vivo neurochemical assays that are reflective of voltage-sensitive calcium channel function. Synthetic ω-GsTx SIA inhibited K+-evoked rat and chick synaptosomal 45Ca2+ flux, K+-evoked release of [3H]D-aspartate and [3H]norepinephrine from rat hippocampal brain slices and K+-evoked release of [3H]norepinephrine from chick cortical brain slices with potency values that were comparable to those found previously with ω-GsTx SIA purified from the venom of the tarantula spider Grammostola spatulata. These results indicate that trace contaminants do not account for the pharmacology of purified ω-GsTx SIA. ω-GsTx SIA caused a complete inhibition of rat synaptosomal 45Ca2+ flux and hippocampal slice [3H]o-aspartate release, whereas ω-Aga-IVA caused a maximal inhibition of approx 75%. ω-GsTx SIA and ω-Aga-IVA caused an identical partial inhibition of K+-evoked increases of intracellular calcium in cortical neurons in primary culture. The addition of nitrendipine to either ω-GsTx SIA or ω-Aga-IVA resulted in an additive and virtually complete inhibition of the cortical neuron intracellular calcium response. In in vivo microdialysis studies, the K+-evoked release of glutamate from hippocampus of awake freely moving rats was inhibited with the following rank order of potency: ω-conotoxin GVIA > ω-GsTx SIA > ω-Aga-IVA. Complete inhibition of K+-evoked hippocampal glutamate release was observed with 300 nM co-conotoxin GVIA and 3 μM ω-GsTx SIA. In urethane anesthetized rats, ω-CgTx GVIA caused a partial inhibition, whereas ω-GsTx SIA caused a concentration-dependent and complete inhibition, of basal serotonin release in the hippocampus. Therefore, ω-GsTx SIA was shown to inhibit responses that are sensitive to ω-conotoxin GVIA, ω-Aga-IVA and ω-conotoxin MVIIC, consistent with the notion that ω-GsTx SIA inhibits N-, P-and Q-type high threshold voltage-sensitive calcium channels.

We also recommend Trading Suppliers and Manufacturers of OMEGA-GRAMMOTOXIN SIA (cas 152617-90-8). Pls Click Website Link as below: cas 152617-90-8 suppliers