[Effect of hypertonic solutions by intravenous route into cerebral perivascular spaces in the dog]

The authors studied the behavior of vessels penetrating the nervous parenchyma in the basal paraolfactory space after an intravenous injection of the hypertonic sodium chloride solution (20/1000), plus a 1% India ink solution injected via subarachnoidal space. The experiments were performed in 10 dogs of different races keeping 6 as controls. The experiment followed Mallory's method and consisted in cutting series of 20 microns sections, going from the surface down to 10mm deep, 10 plates (in each case) of the vessels and the pio-glial membrane were drawn up with the aid of a "camera lucida". The statistical analysis showed a significant enhance in the perivascular space due to the hipertonic solution which seems to results from an osmotic phenomenon through the pio-glial membrane. In this way, the pio-glial membrane can be considered as an active structure in the neuronal-glial-meningeal complex.