Fig. 10.

Low-power (left panel) and high-power (right panel) transmission electronmicrographs (left panel) showing a cerebral capillary and the surrounding neuropil in control (a and b) and METH-treated brain (c and d, 23°; e and f 29° C). Normal cerebral capillary has smooth luminal surface and a compact, dense neuropil surrounding it and normal tight junctions (a, arrow). The normal capillary also has distinct tight junctions (b, arrow) and the underlying glial cells (astrocyte) do not exhibit any apparent signs of perivascular edema (b). METH treatment at 23°C resulted in endothelial cell reaction and swelling of the perivascular astrocyte (*, c). The endothelial luminal surface exhibited few distinct bleb formations (arrow head) indicating the process of enhanced vesicular transport or alterations in membrane transport properties (d, for details see text). Swollen perivascular astrocytes and its processes (*) are evident in this METH-treated rat (d). These ultratstructural changes, e.g., bleb formation and perivascular edema, were much more aggravated in the rat after METH treatment at 29°C (e, f). Thus, spreading out of small membrane vesicles and elongated bleb formation could be seen in this group (arrow heads). Swelling of astrocytes (*) and disintegration of astrocytic cytoplasm indicating water filled cells are clearly visible (*, f). The endothelial cell cytoplasm in METH-treated rats shows much condense cytoplasm (d, f) compared to control (a, b). Bars: a, c = 1 µm, e = 2 µm; b = 500 nm; d = 800 nm; f = 600 nm.