Synchronization dynamics induced on pairs of neurons under applied weak alternating magnetic fields.

Pairs of Helix aspersa neurons show an alternating magnetic field dependent frequency synchronization (AMFS) when exposed to a weak (amplitude B0 between 0.2 and 150 Gauss (G)) alternating magnetic field (AMF) of extremely low frequency (ELF, fM = 50 Hz). We have compared the AMFS patterns of discharge with: i) the synaptic activity promoted by glutamate and acetylcholine; ii) the activity induced by caffeine; iii) the bioelectric activity induced on neurons interconnected by electric synapses. AMFS activity reveals several specific features: i) a tight coincidence in time of the pattern and frequency, f, of discharge; ii) it is induced in the time interval of field application; iii) it is dependent on the intensity of the sinusoidal applied magnetic field; iv) elicited biphasic responses (excitation followed by inhibition) run in parallel for the pair of neurons; and v) some neuron pairs either spontaneously or AMF synchronized can be desynchronized under applied higher AMF. Our electron microscopy studies reveal gap-like junctions confirming our immunocytochemistry results about expression of connexin 26 (Cx26) in 4.7% of Helix neurons. AMF and carbenoxolone did not induce any significant effect on spontaneous synchronization through electric synapses.

Células madre satélite musculares en el modelo de ELA murino hSOD-1G93A / No disponible

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A genetic fusion GDNF-C fragment of tetanus toxin prolongs survival in a symptomatic mouse ALS model.

PURPOSE: Amyotrophic Lateral Sclerosis (ALS) is a paralyzing disorder that kills individuals within three to five years of onset without any possibility for effective treatment. One proposed therapy has been the use of neurotrophic factors to inhibit the apoptosis of motorneurones. At the present, one way to deliver neurotrophic factors after intramuscular injection to the motor neurones is through the use of adenoviral vectors. An alternative strategy is the use of the atoxic C fragment of tetanus toxin (TTC) as a neurotrophic factor carrier for motorneurones. METHODS: We have produced the recombinant protein fusion Glial Derived Neurotrophic Factor and C fragment of tetanus toxin (GDNF-TTC) and we have tested its antiapoptotic activity in degeneration culture cells and in the symptomatic SOD;{G93A} transgenic animal model for ALS. RESULTS: We demonstrated that GDNF-TTC induces the neuronal survival Akt kinase pathway in mouse cortical culture neurons and~maintains its antiapoptotic neuronal activity in Neuro2A cells. Moreover, we have found that genetic fusion is able to increase survival by 9 days and improves life quality in symptomatic ALS animal models. CONCLUSION: These results suggest that recombinant GDNF-TTC fusion protein intramuscular injections provide a potential therapy for ALS treatment.

Synaptic neurone activity under applied 50 Hz alternating magnetic fields.

The effect of 50 Hz alternating magnetic fields of 10-150 Gauss (1-15 mT) intensity on neurone synaptic activity for glutamate and acetylcholine has been studied. The applied 50 Hz alternating magnetic field does not modify the synaptic activity induced by glutamate or acetylcholine on neurones. It has been observed that both caffeine and glutamate induce similar effects, either stimulation or inhibition, on different neurone types. It is shown that applied 50 Hz alternating magnetic fields mimic the synaptic effect of glutamate. A mimic effect has also been observed between the induced effect by applying 50 Hz alternating magnetic field on neurones and the one induced by caffeine and glutamate on the same neurone. The application of Ringer solutions with different concentrations of Ca2+/K+ ions suggest that Ca2+ ions are involved in the elicited responses to either caffeine, glutamate or 50 Hz magnetic fields. Our conclusion is that the observed mimic induced effects for 50 Hz alternating magnetic fields, caffeine and glutamate on neurones corroborate that Ca2+ ions are the cytosolic effectors of the applied 50 Hz alternating magnetic fields interaction with neurone plasma membrane.