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Figure 11. The two tracings show the electrical currents from cultured hippocampal neurons. The initial , essentially flat lines interrupted by a few random spikes of current is the quiescent state maintained by kynurenic acid (5 µM) added to the culture medium. When the kynurenic acid was washed of the hippocampal neuron the dense black area results form a fusion of electrical spikes indicating suicidal electrical activity, which would kill the cell from depletion of ATP. Addition of the kynurenic acid to the bathing medium terminated the hyper electrical response of the neuron returning it to an electrically quiescent state and the tracing is again flat. When the kynurenic acid was washed out of the bathing medium EPA (20 µM) was added to the perfusion fluid. The initial great burst of activity was not prevented, but very soon the electrical activity was reduced so as not to be suicidal. The lower tracing shows a repetition of the experiment.

As shown in Figure 11, we first ran a control in which the kyneurenic acid was washed out causing a burst of electrical activity. Before this killed the neuron we added back the kynuerenic acid and the neuron became electrically quiet again. Then we added EPA (15 µM) to the bathing medium. This did not prevent an initial very short burst of electrical hyperactivity. Quickly, however, the activity slowed down to a non-suicidal rate, which persisted until the EPA was extracted from the neuron with delipidated bovine serum albumin. The suicidal electrical activity then recommenced and the kynuerenic acid was promptly reapplied. We were of course surprised, but very pleased, that the EPA effectively prevented the suicidal activity of the neuron, so we repeated our experiment with identical results. Unfortunately, we did not succeed to have this experiment repeated again on a different sample of cultured neurons, as Professor Furshpan had other interests to pursue.