Methods for neuronal guiding and synapse formation

Hypothesis: Light at certain wavelengths, can cross the cell, tissue sections and organ tissues for in-vitro studies, but can also be used for in-vivo studies. The ability to guide the growth of neural extensions was proven by laser. Synapses produced with laser have the instability as main disadvantage, in the absence of high densities of neurons. The main mechanism of synapse formation is the synaptic plasticity. In this case, dendritic learning spines increase in size and are transformed in dendritic memory spines. Aim: The goal of this study was to evaluate if the creation of synapses using laser, without cell disruptions, is feasible. Methods and Results: We have stimulated neuronal guiding growth using a laser system called multipoint optical tweezers. Approaches were made between dendrites and neuronal bodies. Normal mechanism of synapses formation was stimulated by using electrical stimuli, applied by using a patch-clamp set-up. This approach revealed the transmission of electrical stimuli on both sides of the synapse, but also its unidirectional transmission, which is correlated with cell integrity. Discussion: The feasibility of achieving laser synapses was proven, and this method can be useful for the development of neural circuits, and for the modulation of the existing ones. We suggest that light is the best tool to guide neural growth and synapse formation. This method is cost efficient and very easy to perform. Our model is very good for understanding molecular mechanisms in pathological neurons that are relocated in key positions from pathological tissues or from transfected cell lines.