Schützt potenziertes Glutamat vor Neurotoxizität?

Background: Glutamate is a neurotoxic substance which is held responsible for some of the damage observed in stroke. In an animal stroke model (primary rat spinal, cortical and cerebellar neurons) the protective effects of ultra-low doses (ULD) of glutamate against glutamate toxicity were studied. Method: Neurons were exposed to four subtoxic, ultra-low concentrations of glutamate (10–18 M, 10–20 M, 10–22 M and 10–30 M; i.e. homeopathic potencies of C18, C20, C22 and C30) for 72 h and then subsequently challenged with toxic concentrations (25 μM) of glutamate. Results: Neuron viability was consistently 10% higher in spinal and cortical neurons pre-exposed to glutamate concentrations of 10–18 M and 10–22 M, and in cerebellar neurons pre-exposed to 10–20 M and 10–30 M. Using laser scanning confocal microscopy and the fluorescent calcium probe fluo-3, we found no alterations in intracellular calcium dynamics in the protected cells. This protective effect is consistent with a growing body of evidence for tolerance induced by low-dose toxin exposure but is the first time that such tolerance has been demonstrated with ultra-low glutamate exposure. Conclusion: Our data show that pre-exposure of neuronal cells to ULD glutamate can protect against subsequent exposure to toxic levels of glutamate.