AI Article Synopsis
- A novel polypeptide toxin named Lsp-1 was discovered in the venom of the spider Lycosa, which affects P-type calcium channels in Purkinje neurons.
- Lsp-1 significantly slows the activation of these channels and reduces the current amplitude without altering the channel's deactivation or inactivation.
- The effects of Lsp-1 are partially reversible and not influenced by G-proteins, suggesting its potential as a pharmacological tool for studying P-channels due to their crucial role in neuronal function.
Article Abstract
We have identified a novel polypeptide toxin (Lsp-1) from the venom of the spider Lycosa (LS). Its effect has been examined on the P-type calcium channels in Purkinje neurons, using whole-cell patch-clamp. This toxin (at saturating concentration 7 nM) produces prominent (four-fold) deceleration of the activation kinetics and partial (71+/-6%) decrease of the amplitude of P-current without affecting either deactivation or inactivation kinetics. These effects are not use-dependent. They are partially reversible within a minute upon the wash-out of the toxin. Intracellular perfusion of Purkinje neurons with 100 microM of GDP or 2 microM of GTPgammaS, as well as strong depolarising pre-pulses (+100 mV), do not eliminate the action of Lsp-1 on P-channels indicating that down-modulation via guanine nucleotide-binding proteins (G-proteins) is not involved in the observed phenomenon. In view of extremely high functional significance of P-channels, the toxin can be suggested as a useful pharmacological tool.
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| http://dx.doi.org/10.1016/j.tox.2004.09.005 | DOI Listing |
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