Fig. 2
From: Mechanisms of initiation of cortical spreading depression
Effect of blocking the NMDARs on the neuronal depolarization elicited near the site of CSD induction by CSD threshold and just subthreshold KCl stimuli. A Representative membrane potential traces recorded in response to a CSD threshold KCl stimulus in a L2/3 pyramidal cell located near the KCl puffer (as in Figure 1) in the absence (ctrl, red trace) and presence (MK, blue trace) of MK-801 (50 µM) (upper panel). The corresponding, simultaneously recorded, IOS changes are shown in the lower panel. MK-801 inhibited only 17 % and 24% of the amplitudes (relative to the resting potential) of the 1st and 2nd peak of the depolarization elicited by the CSD threshold stimulus, but completely eliminated the third CSD peak as well as the steep CSD IOS rise. B Average percentage of inhibition by MK-801 (20-50 µM) of the peak amplitudes (relative to resting potential) of the depolarizations elicited in L2/3 pyramidal cells located near the KCl puffer by CSD threshold or slightly suprathreshold KCl stimuli (n = 7, N = 6). 1p, 2p and 3p refer to the 1st, 2nd and 3rd (CSD) peaks of the depolarization, as indicated in Figure 1A. C Representative membrane potential traces recorded in response to a CSD just subthreshold KCl stimulus (40 ms shorter than the threshold stimulus) in the same L2/3 pyramidal cell of panel A in the absence (ctrl, black trace) and presence (MK, blue trace) of MK-801 (50 µM). MK-801 inhibited 14 % and 19 % of the amplitudes of the 1st and 2nd peak of the depolarization elicited by the just subthreshold stimulus, and completely eliminated the shoulder after the 2nd peak, thus decreasing the duration (at half amplitude) of the just subthreshold depolarization from 10.5 to 7.3 s