Figure 2

<p>A. Recostrution of the distribution of NCs superimposed on a coronal section immunoreacted with anti-MAP-2 antibody (immunoperoxydase staining) to identify the ischemic region. Green fluorescent CFDA-stained stem cells were counted and plotted on the adjacent section stained with the MAP-2 fluorescent antibody (calibration bar = 1 cm). In B and C, microphotographs of green fluorescent CFDA-stained stem cells on sections counterstained with the fluorescent anti-MAP-2 antibody are shown at ×10 (B) and ×40 (C) magnifications. The pictures were taken in the transition region between the MAP-2⁺ and the MAP-2⁻ areas in the olfactory region. Calibration bars: 150 µm and 16 µm for B and C, respectively.</p

Experimental protocols.

<p>Ischemia was induced for 30 minutes, 2 hours after the <i>in vitro</i> placement of the isolated brain. NC were perfused for 1 h immediately either after the reopening of the vessel or 1 our later (protocol 2). The perfusion was followed by a wash-out period with a solution without NCs. At 5 hours <i>in vitro</i> the brains were fixed for immunohistochemistry. The bottom of the panel shows an example of simultaneous DC recordings from 4 different sites in an isolated guinea pig brain. Hypoxic depressions (HD) were recorded in the electrodes located in the regions vascularized by the occluded MCA. Potentials evoked by LOT stimulation before and during the first part of ischemia (arrowhead) disappeared when HD occurred, and recovered during MCA reperfusion. Evoked potentials in the hemisphere contralateral to MCA occlusion were not altered.</p

Figure 4

<p>(A) Changes in extracellular pH <u>(pH_e)</u> in the PC and in mOT induced by ipsilateral MCA occlusion and reperfusion. Occlusion induced a rapid metabolic acidification of the extracellular microenviroment in PC, interrupted by a transient and mild basification (arrow) associated to the hypoxic spreading depression (HD, asterisk). No changes in extracellular [H⁺] were recorded in the mOT, that is not served by the MCA. (B) Simultaneous changes in extracellular potassium concentration ([K⁺]_o)and extracellular pH in the PC after MCA occlusion and reperfusion. An initial enhancement in [K⁺] was followed by a fast and large increase in [K⁺]_o. associated to the HD. The schematic drawing on the right illustrates the position of the two-barrel recording electrodes. The field responses (FP) recorded with the conventional extracellular barrel are also shown. The period of MCA occlusion is marked by the shaded area.</p

Mean NCs density (cells/cm²) in the MAP-2 positive zone contralateral (left column) and ipsilateral (middle column) to the ischemic side and in the MAP-2 negative zone of the ischemic hemisphere (right column) in 6 different experiments.

<p>On the left, the number of slices on which counts were made for each experiments is indicated.</p

Confocal fluorescence microscope images of PECAM-1 stained sections (50 µm thick) cut from the piriform region of brains fixed at the end of the electrophysiological experiment.

<p>CFDA green fluorescent NCs and brain vessels are shown at different magnifications. Calibration bar = 100 µm. NCs were observed in close proximity to cerebral vessels.</p