The Plastic Glial-Synaptic Dynamics within the Neuropil: A Self-Organizing System Composed of Polyelectrolytes in Phase Transition

Figure 5

Circling wave experiment recording with calcium sensitive electrode and local potential glass electrodes inserted at the inner plexiform layer. (a) In the initial hour of the experiment, the circling wave spreads with uniform velocity. The extracellular calcium activity falls two log units from 1 to 0.01 mEq/L. The bar shows the change in the perfusion solution from 1 mEq/L to 0.1 mEq/L. Note that the fall in baseline calcium activity at the neuropil is very slow and reaches the value of 0.6 mEq/L at the end of the pulse. The wave transients do not change. Note the slower propagation velocity with low calcium. (b) 40 minutes later, the system returned to control values for the wave concomitants and propagation velocity. Flunarizin 2 µM was applied for 8 minutes. The baseline calcium activity increased to 3.2 mEq/L at the end of the pulse. The wave concomitants were smaller. Note the increase in propagation velocity under the influence of flunarizin. It took 40 minutes of flunarizin washing off for the baseline calcium activity to return to control level. (c) Third hour of circling wave recording, one hour after the last wave in (b). Barium chloride (4 mEq/L) was applied. Note the depression of potential and calcium transient during turning waves. Barium was the agent which could depress the potential drop to zero and slow propagation to a factor of 5 times slower. There was an increase in the baseline calcium and a positive shift in the baseline extracellular potential in the presence of barium (figure modified from [79]).

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